Lighting Systems for Providing Tunable White Light With Functional Diode Emissions

ABSTRACT

The present disclosure provides systems for generating tunable white light. The systems include a plurality of LED strings that generate light with color points that fall within red, blue, and green color ranges, with each LED string being driven with a separately controllable drive current in order to tune the generated light output. The systems can include an additional LED string configured for functional applications that includes a type of LED selected from 380-420 nm violet saturated LEDs, 200-280 nm UVC saturated LEDs, 850-940 nm near-IR saturated LEDs, 580-620 nm amber-orange/red saturated LEDs, and 460-490 nm long-blue saturated LEDs.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of International PatentApplication No. PCT/US2018/020793 filed Mar. 2, 2018, which claims thebenefit of U.S. Provisional Patent Application No. 62/626,423 filed Jan.11, 2018; is a continuation-in-part of International Patent ApplicationNo. PCT/US2016/015402 filed Jan. 28, 2016; is a continuation-in-part ofInternational Patent Application No. PCT/US2016/015385 filed Jan. 28,2016; is a continuation-in-part of International Patent Application No.PCT/US2016/015441 filed Jan. 28, 2016; is a continuation-in-part ofInternational Patent Application No. PCT/US2016/015318 filed Jan. 28,2016; and claims the benefit of U.S. Provisional Patent Application No.62/616,401 filed Jan. 11, 2018; U.S. Provisional Patent Application No.62/616,404 filed Jan. 11, 2018; U.S. Provisional Patent Application No.62/616,414 filed Jan. 11, 2018; U.S. Provisional Patent Application No.62/616,423 filed Jan. 11, 2018; and U.S. Provisional Patent ApplicationNo. 62/634,798 filed Feb. 23, 2018, the contents of which areincorporated by reference herein in their entirety as if fully set forthherein.

FIELD OF THE DISCLOSURE

This disclosure is in the field of solid-state lighting. In particular,the disclosure relates to devices for use in, and methods for, providingtunable white light with high color rendering performance.

BACKGROUND

A wide variety of light emitting devices are known in the art including,for example, incandescent light bulbs, fluorescent lights, andsemiconductor light emitting devices such as light emitting diodes(“LEDs”).

There are a variety of resources utilized to describe the light producedfrom a light emitting device, one commonly used resource is 1931 CIE(Commission Internationale de l'Eclairage) Chromaticity Diagram. The1931 CIE Chromaticity Diagram maps out the human color perception interms of two CIE parameters x and y. The spectral colors are distributedaround the edge of the outlined space, which includes all of the huesperceived by the human eye. The boundary line represents maximumsaturation for the spectral colors, and the interior portion representsless saturated colors including white light. The diagram also depictsthe Planckian locus, also referred to as the black body locus (BBL),with correlated color temperatures, which represents the chromaticitycoordinates (i.e., color points) that correspond to radiation from ablack-body at different temperatures. Illuminants that produce light onor near the BBL can thus be described in terms of their correlated colortemperatures (CCT). These illuminants yield pleasing “white light” tohuman observers, with general illumination typically utilizing CCTvalues between 1,800K and 10,000K.

Color rendering index (CRI) is described as an indication of thevibrancy of the color of light being produced by a light source. Inpractical terms, the CRI is a relative measure of the shift in surfacecolor of an object when lit by a particular lamp as compared to areference light source, typically either a black-body radiator or thedaylight spectrum. The higher the CRI value for a particular lightsource, the better that the light source renders the colors of variousobjects it is used to illuminate.

Color rendering performance may be characterized via standard metricsknown in the art. Fidelity Index (Rf) and the Gamut Index (Rg) can becalculated based on the color rendition of a light source for 99 colorevaluation samples (“CES”). The 99 CES provide uniform color spacecoverage, are intended to be spectral sensitivity neutral, and providecolor samples that correspond to a variety of real objects. Rf valuesrange from 0 to 100 and indicate the fidelity with which a light sourcerenders colors as compared with a reference illuminant. In practicalterms, the Rf is a relative measure of the shift in surface color of anobject when lit by a particular lamp as compared to a reference lightsource, typically either a black-body radiator or the daylight spectrum.The higher the Rf value for a particular light source, the better thatthe light source renders the colors of various objects it is used toilluminate. The Gamut Index Rg evaluates how well a light sourcesaturates or desaturates the 99 CES compared to the reference source.

LEDs have the potential to exhibit very high power efficiencies relativeto conventional incandescent or fluorescent lights. Most LEDs aresubstantially monochromatic light sources that appear to emit lighthaving a single color. Thus, the spectral power distribution of thelight emitted by most LEDs is tightly centered about a “peak”wavelength, which is the single wavelength where the spectral powerdistribution or “emission spectrum” of the LED reaches its maximum asdetected by a photo-detector. LEDs typically have a full-widthhalf-maximum wavelength range of about 10 nm to 30 nm, comparativelynarrow with respect to the broad range of visible light to the humaneye, which ranges from approximately from 380 nm to 800 nm.

In order to use LEDs to generate white light, LED lamps have beenprovided that include two or more LEDs that each emit a light of adifferent color. The different colors combine to produce a desiredintensity and/or color of white light. For example, by simultaneouslyenergizing red, green and blue LEDs, the resulting combined light mayappear white, or nearly white, depending on, for example, the relativeintensities, peak wavelengths and spectral power distributions of thesource red, green and blue LEDs. The aggregate emissions from red,green, and blue LEDs typically provide poor color rendering for generalillumination applications due to the gaps in the spectral powerdistribution in regions remote from the peak wavelengths of the LEDs.

White light may also be produced by utilizing one or more luminescentmaterials such as phosphors to convert some of the light emitted by oneor more LEDs to light of one or more other colors. The combination ofthe light emitted by the LEDs that is not converted by the luminescentmaterial(s) and the light of other colors that are emitted by theluminescent material(s) may produce a white or near-white light.

LED lamps have been provided that can emit white light with differentCCT values within a range. Such lamps utilize two or more LEDs, with orwithout luminescent materials, with respective drive currents that areincreased or decreased to increase or decrease the amount of lightemitted by each LED. By controllably altering the power to the variousLEDs in the lamp, the overall light emitted can be tuned to differentCCT values. The range of CCT values that can be provided with adequatecolor rendering values and efficiency is limited by the selection ofLEDs.

The spectral profiles of light emitted by white artificial lighting canimpact circadian physiology, alertness, and cognitive performancelevels. Bright artificial light can be used in a number of therapeuticapplications, such as in the treatment of seasonal affective disorder(SAD), certain sleep problems, depression, jet lag, sleep disturbancesin those with Parkinson's disease, the health consequences associatedwith shift work, and the resetting of the human circadian clock.Artificial lighting may change natural processes, interfere withmelatonin production, or disrupt the circadian rhythm. Blue light mayhave a greater tendency than other colored light to affect livingorganisms through the disruption of their biological processes which canrely upon natural cycles of daylight and darkness. Exposure to bluelight late in the evening and at night may be detrimental to one'shealth. Some blue or royal blue light within lower wavelengths can havehazardous effects to human eyes and skin, such as causing damage to theretina.

Significant challenges remain in providing LED lamps that can providewhite light across a range of CCT values while simultaneously achievinghigh efficiencies, high luminous flux, good color rendering, andacceptable color stability. It is also a challenge to provide lightingapparatuses that can provide desirable lighting performance whileallowing for the control of circadian energy performance.

DISCLOSURE

The present disclosure provides aspects of semiconductor light emittingdevices comprising first, second, and third LED strings, with each LEDstring comprising one or more LEDs having an associated luminophoricmedium. The first, second, and third LED strings together with theirassociated luminophoric mediums can comprise red, blue, and greenchannels respectively, producing first, second, and third unsaturatedcolor points within red, blue, and green regions on the 1931 CIEChromaticity diagram, respectively. A control circuit can be configuredto adjust a fourth color point of a fourth unsaturated light thatresults from a combination of the first, second, and third unsaturatedlight, with the fourth color point falls within a 7-step MacAdam ellipsearound any point on the black body locus having a correlated colortemperature between 1800K and 10000K. The devices can be configured togenerate the fourth unsaturated light corresponding to a plurality ofpoints along a predefined path with the light generated at each pointhaving light with Rf greater than or equal to about 85, Rg greater thanor equal to about 90 and less than or equal to about 110, or both. Thedevices can be configured to generate the fourth unsaturated lightcorresponding to a plurality of points along a predefined path with thelight generated at each point having light with Ra greater than or equalto about 92 along points with correlated color temperature between about1800K and 10000K, R9 greater than or equal to 80 along points withcorrelated color temperature between about 2100K and about 10000K, orboth. The devices can be configured to generate the fourth unsaturatedlight corresponding to a plurality of points along a predefined pathwith the light generated at each point having EML greater than or equalto about 0.5 along points with correlated color temperature above about2400K, EML greater than or equal to about 1.0 along points withcorrelated color temperature above about 5500K, or both. The devices canbe configured to generate the fourth unsaturated light corresponding toa plurality of points along a predefined path with the light generatedat each point having light with R13 greater than or equal to about 92,R15 greater than or equal to about 88, or both. The blue color regioncan be a region on the 1931 CIE Chromaticity Diagram defined by a lineconnecting the ccx, ccy color coordinates of the infinity point of thePlanckian locus (0.242, 0.24) and (0.12, 0.068), the Planckian locusfrom 4000K and infinite CCT, the constant CCT line of 4000K, the line ofpurples, and the spectral locus. The red color region can be a region onthe 1931 CIE Chromaticity Diagram defined by the spectral locus betweenthe constant CCT line of 1600K and the line of purples, the line ofpurples, a line connecting the ccx, ccy color coordinates (0.61, 0.21)and (0.47, 0.28), and the constant CCT line of 1600K. The green colorregion can be a region on the 1931 CIE Chromaticity Diagram defined bythe constant CCT line of 6700K, the Planckian locus, and the spectrallocus. The spectral power distributions for the red, blue, and greenchannels can fall within the minimum and maximum ranges shown in Tables1 and 2. The present disclosure provides aspects of semiconductor lightemitting devices comprising the first, second, and third LED strings anda fourth LED string. The fourth LED string can comprise a type of LEDselected from 380-420 nm violet saturated LEDs, 200-280 nm UVC saturatedLEDs, 850-940 nm near-IR saturated LEDs, 580-620 nm amber-orange/redsaturated LEDs, and 460-490 nm long-blue saturated LEDs. The controlcircuit can be further configured to adjust a sixth color point of asixth unsaturated light that results from a combination of the first,second, and third unsaturated light and the a fifth saturated lightgenerated by the fourth LED string, with the sixth color point fallingwithin a 7-step MacAdam ellipse around any point on the black body locushaving a correlated color temperature between 1800K and 10000K. The LEDsof the fourth LED string can comprise 380-420 nm violet saturated LEDsand the device can be configured to generate the sixth unsaturated lightcorresponding to a plurality of points along a predefined path with oneor more of the following: the light generated at each point having lightwith Rf greater than or equal to about 85, Rg greater than or equal toabout 95 and less than or equal to about 103, or both; the lightgenerated at each point having light with Rf greater than or equal toabout 90, Rg greater than or equal to about 97 and less than or equal toabout 103, or both; the light generated at each point having light withRf greater than or equal to about 90, Rg greater than or equal to about99 and less than or equal to about 103, or both; the light generated ateach point having light with Rf greater than or equal to about 90, Rggreater than or equal to about 97 and less than or equal to about 101,or both; the light generated at each point having light with Ra greaterthan or equal to about 93 along points with correlated color temperaturebetween about 1800K and 10000K, R9 greater than or equal to 85 alongpoints with correlated color temperature between about 1800K and about10000K, or both; the light generated at each point having one or more ofEML greater than or equal to about 0.5 along points with correlatedcolor temperature above about 2700K, EML greater than or equal to about0.75 along points with correlated color temperature above about 4000K,EML greater than or equal to about 1.0 along points with correlatedcolor temperature above about 5500K, and EML greater than or equal toabout 1.2 along points with correlated color temperature above about8000K; the light generated at each point having light with R13 greaterthan or equal to about 94, R15 greater than or equal to about 90, orboth; the light generated at each point having light with R13 greaterthan or equal to about 95, R15 greater than or equal to about 92, orboth; and the light generated at each point having light with R13greater than or equal to about 94, R15 greater than or equal to about95, or both.

In some aspects, the present disclosure provides methods of generatingwhite light, the methods comprising providing first, second, and thirdLED strings, with each LED string comprising one or more LEDs having anassociated luminophoric medium, providing a fourth LED string, whereinthe first, second, and third LED strings together with their associatedluminophoric mediums comprise red, blue, and green channelsrespectively, producing first, second, and third unsaturated light withcolor points within red, blue, and green regions on the 1931 CIEChromaticity diagram, respectively, providing a control circuitconfigured to adjust a fourth color point of a fourth unsaturated lightthat results from a combination of the first, second, and third,unsaturated light, with the fourth color point falls within a 7-stepMacAdam ellipse around any point on the black body locus having acorrelated color temperature between 1800K and 10000K, wherein thecontrol circuit is further configured to adjust a sixth color point of asixth unsaturated light that results from a combination of the first,second, and third unsaturated light and a fifth saturated light from thefourth LED string, generating light in a first operating mode with twoor more of the first, second, and third unsaturated light by combiningthe two or more generated unsaturated lights to create the fourthunsaturated light, and generating light in a second operating mode withtwo or more of the first, second, and third unsaturated light and thefifth saturated light by combining the two or more generatedunsaturated/saturated light to create the sixth unsaturated light. Insome implementations, the LEDs of the fourth LED string comprise a typeof LED selected from 380-420 nm violet saturated LEDs, 200-280 nm UVCsaturated LEDs, 850-940 nm near-IR saturated LEDs, 580-620 nmamber-orange/red saturated LEDs, and 460-490 nm long-blue saturatedLEDs. In some implementations, the LEDs of the fourth LED stringcomprise 380-420 nm violet saturated LEDs. In some implementations, theLEDs of the fourth LED string comprise 200-280 nm UVC saturated LEDs. Insome implementations, the LEDs of the fourth LED string comprise 850-940nm near-IR saturated LEDs. In some implementations, the LEDs of thefourth LED string comprise 580-620 nm amber-orange/red saturated LEDs.In some implementations, the control circuit can be configured to switchbetween the first operating mode and the second operating mode toprovide the fourth unsaturated light and the sixth unsaturated lighthaving substantially the same ccx, ccy coordinates on the 1931 CIEChromaticity Diagram. In some implementations, the fourth unsaturatedlight and the sixth unsaturated light can have color points within about1.0 standard deviations of color matching (SDCM). In someimplementations, the fourth unsaturated light and the sixth unsaturatedlight can have color points within about 0.5 standard deviations ofcolor matching (SDCM). In some implementations, the sixth unsaturatedlight can have improved color-rendering performance in comparison to thefourth unsaturated light in one or more of Ra, R9, Rf, and Rg.

The general disclosure and the following further disclosure areexemplary and explanatory only and are not restrictive of thedisclosure, as defined in the appended claims. Other aspects of thepresent disclosure will be apparent to those skilled in the art in viewof the details as provided herein. In the figures, like referencenumerals designate corresponding parts throughout the different views.All callouts and annotations are hereby incorporated by this referenceas if fully set forth herein.

DRAWINGS

The summary, as well as the following detailed description, is furtherunderstood when read in conjunction with the appended drawings. For thepurpose of illustrating the disclosure, there are shown in the drawingsexemplary implementations of the disclosure; however, the disclosure isnot limited to the specific methods, compositions, and devicesdisclosed. In addition, the drawings are not necessarily drawn to scale.In the drawings:

FIG. 1 illustrates aspects of light emitting devices according to thepresent disclosure;

FIG. 2 illustrates aspects of light emitting devices according to thepresent disclosure;

FIG. 3 depicts a graph of a 1931 CIE Chromaticity Diagram illustratingthe location of the Planckian locus;

FIGS. 4A-4D illustrate some aspects of light emitting devices accordingto the present disclosure, including some suitable color ranges forlight generated by components of the devices;

FIG. 5 illustrates some aspects of light emitting devices according tothe present disclosure, including some suitable color ranges for lightgenerated by components of the devices;

FIG. 6 illustrates some aspects of light emitting devices according tothe present disclosure, including some suitable color ranges for lightgenerated by components of the devices;

FIGS. 7A-7F show tables of data of color rendering characteristics of animplementation of the present disclosure;

FIGS. 8A-8F are tables of data of relative spectral power versuswavelength regions for some suitable color points of light generated bycomponents of devices of the present disclosure; and

FIGS. 9A-9F are tables of data of relative spectral power versuswavelength regions for some suitable color points of light generated bycomponents of devices of the present disclosure.

All descriptions and callouts in the Figures are hereby incorporated bythis reference as if fully set forth herein.

FURTHER DISCLOSURE

The present disclosure may be understood more readily by reference tothe following detailed description taken in connection with theaccompanying figures and examples, which form a part of this disclosure.It is to be understood that this disclosure is not limited to thespecific devices, methods, applications, conditions or parametersdescribed and/or shown herein, and that the terminology used herein isfor the purpose of describing particular exemplars by way of exampleonly and is not intended to be limiting of the claimed disclosure. Also,as used in the specification including the appended claims, the singularforms “a,” “an,” and “the” include the plural, and reference to aparticular numerical value includes at least that particular value,unless the context clearly dictates otherwise. The term “plurality”, asused herein, means more than one. When a range of values is expressed,another exemplar includes from the one particular value and/or to theother particular value. Similarly, when values are expressed asapproximations, by use of the antecedent “about,” it will be understoodthat the particular value forms another exemplar. All ranges areinclusive and combinable.

It is to be appreciated that certain features of the disclosure whichare, for clarity, described herein in the context of separate exemplar,may also be provided in combination in a single exemplaryimplementation. Conversely, various features of the disclosure that are,for brevity, described in the context of a single exemplaryimplementation, may also be provided separately or in anysubcombination. Further, reference to values stated in ranges includeeach and every value within that range.

In one aspect, the present disclosure provides semiconductor lightemitting devices 100 that can have a plurality of light emitting diode(LED) strings. Each LED string can have one, or more than one, LED. Asdepicted schematically in FIG. 1, the device 100 may comprise one ormore LED strings (101A/101B/101C/101D) that emit light (schematicallyshown with arrows). In some instances, the LED strings can haverecipient luminophoric mediums (102A/102B/102C/102D) associatedtherewith. The light emitted from the LED strings, combined with lightemitted from the recipient luminophoric mediums, can be passed throughone or more optical elements 103. Optical elements 103 may be one ormore diffusers, lenses, light guides, reflective elements, orcombinations thereof. In some implementations, one or more of the LEDstrings 101A/101B/101C/101D may be provided without an associatedluminophoric medium. In further implementations, three of the LEDstrings 101A/101B/101C can be provided with an associated luminophoricmedium for each, and the fourth LED string 101D can be provided withoutan associated luminophoric medium.

A recipient luminophoric medium 102A, 102B, 102C, or 102D includes oneor more luminescent materials and is positioned to receive light that isemitted by an LED or other semiconductor light emitting device. In someimplementations, recipient luminophoric mediums include layers havingluminescent materials that are coated or sprayed directly onto asemiconductor light emitting device or on surfaces of the packagingthereof, and clear encapsulants that include luminescent materials thatare arranged to partially or fully cover a semiconductor light emittingdevice. A recipient luminophoric medium may include one medium layer orthe like in which one or more luminescent materials are mixed, multiplestacked layers or mediums, each of which may include one or more of thesame or different luminescent materials, and/or multiple spaced apartlayers or mediums, each of which may include the same or differentluminescent materials. Suitable encapsulants are known by those skilledin the art and have suitable optical, mechanical, chemical, and thermalcharacteristics. In some implementations, encapsulants can includedimethyl silicone, phenyl silicone, epoxies, acrylics, andpolycarbonates. In some implementations, a recipient luminophoric mediumcan be spatially separated (i.e., remotely located) from an LED orsurfaces of the packaging thereof. In some implementations, such spatialsegregation may involve separation of a distance of at least about 1 mm,at least about 2 mm, at least about 5 mm, or at least about 10 mm. Incertain embodiments, conductive thermal communication between aspatially segregated luminophoric medium and one or more electricallyactivated emitters is not substantial. Luminescent materials can includephosphors, scintillators, day glow tapes, nanophosphors, inks that glowin visible spectrum upon illumination with light, semiconductor quantumdots, or combinations thereof. In some implementations, the luminescentmaterials may comprise phosphors comprising one or more of the followingmaterials: BaMg₂Al₁₆O₂₇:Eu²⁺, BaMg₂Al₁₆O₂₇:Eu²⁺,Mn²⁺, CaSiO₃:Pb,Mn,CaWO₄:Pb, MgWO₄, Sr₅Cl(PO₄)₃:Eu²⁺, Sr₂P₂O₇:Sn²⁺, Sr₆P₅BO₂₀:Eu,Ca₅F(PO₄)₃:Sb, (Ba,Ti)₂P₂O₇:Ti, Sr₅F(PO₄)₃:Sb,Mn, (La,Ce,Tb)PO₄:Ce,Tb,(Ca,Zn,Mg)₃(PO₄)₂:Sn, (Sr,Mg)₃(PO₄)₂:Sn, Y₂O₃:Eu³⁺, Mg₄(F)GeO₆:Mn,LaMgAl₁₁O₁₉:Ce, LaPO₄:Ce, SrAl₁₂O₁₉:Ce, BaSi₂O₅:Pb, SrB₄O₇:Eu,Sr₂MgSi₂O₇:Pb, Gd₂O₂S:Tb, Gd₂O₂S:Eu, Gd₂O₂S:Pr, Gd₂O₂S:Pr,Ce,F,Y₂O₂S:Tb, Y₂O₂S:Eu, Y₂O₂S:Pr, Zn(0.5)Cd(0.4)S:Ag, Zn(0.4)Cd(0.6)S:Ag,Y₂SiO₅:Ce, YAlO₃:Ce, Y₃(Al,Ga)₅O₁₂:Ce, CdS:In, ZnO:Ga, ZnO:Zn,(Zn,Cd)S:Cu,Al, ZnCdS:Ag,Cu, ZnS:Ag, ZnS:Cu, NaI:Tl, CsI:Tl,⁶LiF/ZnS:Ag, ⁶LiF/ZnS:Cu,Al,Au, ZnS:Cu,Al, ZnS:Cu,Au,Al, CaAlSiN₃:Eu,(Sr,Ca)AlSiN₃:Eu, (Ba,Ca,Sr,Mg)₂SiO₄:Eu, Lu₃Al₅O₁₂:Ce,Eu³⁺(Gd_(0.9)Y_(0.1))₃Al₅O₁₂:Bi³⁺,Tb³⁺, Y₃A₁₅O₁₂:Ce, (La,Y)₃Si₆N₁₁:Ce,Ca₂AlSi₃O₂N₅:Ce³⁺, Ca₂AlSi₃O₂N₅:Eu²⁺, BaMgAl₁₀O₁₇:Eu, Sr₅(PO₄)₃Cl:Eu,(Ba,Ca,Sr,Mg)₂SiO₄:Eu, Si_(6-z)Al_(z)N_(8-z)O_(z):Eu (wherein 0<z≤4.2);M₃Si₆O₁₂N₂:Eu (wherein M=alkaline earth metal element),(Mg,Ca,Sr,Ba)Si₂O₂N₂:Eu, Sr₄Al₁₄O₂₅:Eu, (Ba,Sr,Ca)Al₂O₄:Eu,(Sr,Ba)Al₂Si₂O₈:Eu, (Ba,Mg)₂SiO₄:Eu, (Ba,Sr,Ca)₂(Mg, Zn)Si₂O₇:Eu,(Ba,Ca,Sr,Mg)₉(Sc,Y,Lu,Gd)₂(Si,Ge)₆O₂₄:Eu, Y₂SiO₅:CeTb,Sr₂P₂O₇—Sr₂B₂O₅:Eu, Sr₂Si₃O₈₋₂SrCl₂:Eu, Zn₂SiO₄:Mn, CeMgAl₁₁O₁₉:Tb,Y₃A₁₅O₁₂:Tb, Ca₂Y₈(SiO₄)₆O₂:Tb, La₃Ga₅SiO₁₄:Tb,(Sr,Ba,Ca)Ga₂S₄:Eu,Tb,Sm, Y₃(Al,Ga)₅O₁₂:Ce,(Y,Ga,Tb,La,Sm,Pr,Lu)₃(Al,Ga)₅O₁₂:Ce, Ca₃Sc₂Si₃O₁₂:Ce,Ca₃(Sc,Mg,Na,Li)₂Si₃O₁₂:Ce, CaSc₂O₄:Ce, Eu-activated SrAl₂O₄:Eu,(La,Gd,Y)₂O₂S:Tb, CeLaPO₄:Tb, ZnS:Cu,Al, ZnS:Cu,Au,Al,(Y,Ga,Lu,Sc,La)BO₃:Ce,Tb, Na₂Gd₂B₂O₇:Ce,Tb,(Ba,Sr)₂(Ca,Mg,Zn)B₂O₆:K,Ce,Tb, Ca₈Mg (SiO₄)₄Cl₂:Eu,Mn,(Sr,Ca,Ba)(Al,Ga,In)₂S₄:Eu, (Ca,Sr)₈ (Mg,Zn)(SiO₄)₄Cl₂:Eu,Mn,M₃Si₆O₉N₄:Eu, Sr₅Al₅Si₂₁O₂N₃₅:Eu, Sr₃Si₁₃A₁₃N₂₁O₂:Eu,(Mg,Ca,Sr,Ba)₂Si₅N₈:Eu, (La,Y)₂O₂S:Eu, (Y,La,Gd,Lu)₂O₂S:Eu, Y(V,P)O₄:Eu,(Ba,Mg)₂SiO₄:Eu,Mn, (Ba,Sr, Ca,Mg)₂SiO₄:Eu,Mn, LiW₂O₈:Eu, LiW₂O₈:Eu,Sm,Eu₂W₂O₉, Eu₂W₂O₉:Nb and Eu₂W₂O₉:Sm, (Ca,Sr)S:Eu, YAlO₃:Eu,Ca₂Y₈(SiO₄)₆O₂:Eu, LiY₉(SiO₄)₆O₂:Eu, (Y,Gd)₃Al₅O₁₂:Ce,(Tb,Gd)₃Al₅O₁₂:Ce, (Mg,Ca,Sr,Ba)₂Si₅(N,O)₈:Eu, (Mg,Ca,Sr,Ba)Si(N,O)₂:Eu,(Mg,Ca,Sr,Ba)AlSi(N,O)₃:Eu, (Sr,Ca,Ba,Mg)₁₀(PO₄)₆C₁₂:Eu, Mn,Eu,Ba₃MgSi₂O₈:Eu,Mn, (Ba,Sr,Ca,Mg)₃(Zn,Mg)Si₂O₈:Eu,Mn,(k-x)MgO.xAF₂.GeO₂:yMn⁴⁺ (wherein k=2.8 to 5, x=0.1 to 0.7, y=0.005 to0.015, A=Ca, Sr, Ba, Zn or a mixture thereof), Eu-activated α-Sialon,(Gd,Y,Lu,La)₂O₃:Eu, Bi, (Gd,Y,Lu,La)₂O₂S:Eu,Bi, (Gd,Y, Lu,La)VO₄:Eu,Bi,SrY₂S₄:Eu,Ce, CaLa₂S₄:Ce,Eu, (Ba,Sr,Ca)MgP₂O₇:Eu, Mn,(Sr,Ca,Ba,Mg,Zn)₂P₂O₇:Eu,Mn, (Y,Lu)₂WO₆:Eu,Ma, (Ba,Sr,Ca)xSiyNz:Eu,Ce(wherein x, y and z are integers equal to or greater than1),(Ca,Sr,Ba,Mg)₁₀(PO₄)₆(F,Cl,Br,OH):Eu,Mn,((Y,Lu,Gd,Tb)_(1-x-y)Sc_(x)Ce_(y))₂(Ca,Mg)(Mg,Zn)_(2+r)Si_(z-q)Ge_(q)O_(12+δ),SrAlSi₄N₇, Sr₂Al₂Si₉O₂N₁₄:Eu, M¹ _(a)M² _(b)M³ _(c)O_(d) (whereinM¹=activator element including at least Ce, M²=bivalent metal element,M³=trivalent metal element, 0.0001≤a≤0.2, 0.8≤b≤1.2, 1.6≤c≤2.4 and3.2≤d≤4.8), A_(2+x)M_(y)Mn_(z)F_(n)(wherein A=Na and/or K; M=Si and Al,and −1≤x≤1, 0.001≤z≤0.4 and 5≤n≤7), KSF/KSNAF, or (La_(1-x-y), Eu_(x),Ln_(y))₂O₂S (wherein 0.02≤x≤0.50 and Ln=Y³⁺, Gd³⁺, Lu³⁺, Sc³⁺, Sm³⁺ orEr³⁺). In some preferred implementations, the luminescent materials maycomprise phosphors comprising one or more of the following materials:CaAlSiN₃:Eu, (Sr,Ca)AlSiN₃:Eu, BaMgAl₁₀O₁₇:Eu, (Ba,Ca,Sr,Mg)₂SiO₄:Eu,β-SiAlON, Lu₃Al₅O₁₂:Ce, Eu³⁺(Cd_(0.9)Y_(0.1))₃Al₅O₁₂:Bi³⁺,Tb³⁺,Y₃Al₅O₁₂:Ce, La₃Si₆N₁₁:Ce, (La,Y)₃Si₆N₁₁:Ce, Ca₂AlSi₃O₂N₅:Ce³⁺,Ca₂AlSi₃O₂N₅:Ce³⁺,Eu²⁺, Ca₂AlSi₃O₂N₅:Eu²⁺, BaMgAl₁₀O₁₇:Eu²⁺,Sr_(4.5)Eu_(0.5)(PO₄)₃C₁, or M¹ _(a)M² _(b)M³ _(c)O_(d). (whereinM¹=activator element comprising Ce, M²=bivalent metal element,M³=trivalent metal element, 0.0001≤a≤0.2, 0.8≤b≤1.2, 1.6≤c≤2.4 and3.2≤d≤4.8). In further preferred implementations, the luminescentmaterials may comprise phosphors comprising one or more of the followingmaterials: CaAlSiN₃:Eu, BaMgAl₁O₀₁₇:Eu, Lu₃A₁₅O₁₂:Ce, or Y₃A₁₅O₁₂:Ce.

Some implementations of the present invention relate to use of solidstate emitter packages. A solid state emitter package typically includesat least one solid state emitter chip that is enclosed with packagingelements to provide environmental and/or mechanical protection, colorselection, and light focusing, as well as electrical leads, contacts ortraces enabling electrical connection to an external circuit.Encapsulant material, optionally including luminophoric material, may bedisposed over solid state emitters in a solid state emitter package.Multiple solid state emitters may be provided in a single package. Apackage including multiple solid state emitters may include at least oneof the following: a single leadframe arranged to conduct power to thesolid state emitters, a single reflector arranged to reflect at least aportion of light emanating from each solid state emitter, a singlesubmount supporting each solid state emitter, and a single lens arrangedto transmit at least a portion of light emanating from each solid stateemitter. Individual LEDs or groups of LEDs in a solid state package(e.g., wired in series) may be separately controlled. As depictedschematically in FIG. 2, multiple solid state packages 200 may bearranged in a single semiconductor light emitting device 100. Individualsolid state emitter packages or groups of solid state emitter packages(e.g., wired in series) may be separately controlled. Separate controlof individual emitters, groups of emitters, individual packages, orgroups of packages, may be provided by independently applying drivecurrents to the relevant components with control elements known to thoseskilled in the art. In one embodiment, at least one control circuit 201a may include a current supply circuit configured to independently applyan on-state drive current to each individual solid state emitter, groupof solid state emitters, individual solid state emitter package, orgroup of solid state emitter packages. Such control may be responsive toa control signal (optionally including at least one sensor 202 arrangedto sense electrical, optical, and/or thermal properties and/orenvironmental conditions), and a control system 203 may be configured toselectively provide one or more control signals to the at least onecurrent supply circuit. In various embodiments, current to differentcircuits or circuit portions may be pre-set, user-defined, or responsiveto one or more inputs or other control parameters. The design andfabrication of semiconductor light emitting devices are well known tothose skilled in the art, and hence further description thereof will beomitted.

FIG. 3 illustrates a 1931 International Commission on Illumination (CIE)chromaticity diagram. The 1931 CIE Chromaticity diagram is atwo-dimensional chromaticity space in which every visible color isrepresented by a point having x- and y-coordinates. Fully saturated(monochromatic) colors appear on the outer edge of the diagram, whileless saturated colors (which represent a combination of wavelengths)appear on the interior of the diagram. The term “saturated”, as usedherein, means having a purity of at least 85%, the term “purity” havinga well-known meaning to persons skilled in the art, and procedures forcalculating purity being well-known to those of skill in the art. ThePlanckian locus, or black body locus (BBL), represented by line 150 onthe diagram, follows the color an incandescent black body would take inthe chromaticity space as the temperature of the black body changes fromabout 1000K to 10,000 K. The black body locus goes from deep red at lowtemperatures (about 1000 K) through orange, yellowish white, white, andfinally bluish white at very high temperatures. The temperature of ablack body radiator corresponding to a particular color in achromaticity space is referred to as the “correlated color temperature.”In general, light corresponding to a correlated color temperature (CCT)of about 2700 K to about 6500 K is considered to be “white” light. Inparticular, as used herein, “white light” generally refers to lighthaving a chromaticity point that is within a 10-step MacAdam ellipse ofa point on the black body locus having a CCT between 2700K and 6500K.However, it will be understood that tighter or looser definitions ofwhite light can be used if desired. For example, white light can referto light having a chromaticity point that is within a seven step MacAdamellipse of a point on the black body locus having a CCT between 2700Kand 6500K. The distance from the black body locus can be measured in theCIE 1960 chromaticity diagram, and is indicated by the symbol Δuv, orDUV. If the chromaticity point is above the Planckian locus the DUV isdenoted by a positive number; if the chromaticity point is below thelocus, DUV is indicated with a negative number. If the DUV issufficiently positive, the light source may appear greenish or yellowishat the same CCT. If the DUV is sufficiently negative, the light sourcecan appear to be purple or pinkish at the same CCT. Observers may preferlight above or below the Planckian locus for particular CCT values. DUVcalculation methods are well known by those of ordinary skill in the artand are more fully described in ANSI C78.377, American National Standardfor Electric Lamps—Specifications for the Chromaticity of Solid StateLighting (SSL) Products, which is incorporated by reference herein inits entirety for all purposes. A point representing the CIE StandardIlluminant D65 is also shown on the diagram. The D65 illuminant isintended to represent average daylight and has a CCT of approximately6500K and the spectral power distribution is described more fully inJoint ISO/CIE Standard, ISO 10526:1999/CIE 5005/E-1998, CIE StandardIlluminants for Colorimetry, which is incorporated by reference hereinin its entirety for all purposes.

The light emitted by a light source may be represented by a point on achromaticity diagram, such as the 1931 CIE chromaticity diagram, havingcolor coordinates denoted (ccx, ccy) on the X-Y axes of the diagram. Aregion on a chromaticity diagram may represent light sources havingsimilar chromaticity coordinates.

The ability of a light source to accurately reproduce color inilluminated objects can be characterized using the color rendering index(“CRT”), also referred to as the CIE Ra value. The Ra value of a lightsource is a modified average of the relative measurements of how thecolor rendition of an illumination system compares to that of areference black-body radiator or daylight spectrum when illuminatingeight reference colors R1-R8. Thus, the Ra value is a relative measureof the shift in surface color of an object when lit by a particularlamp. The Ra value equals 100 if the color coordinates of a set of testcolors being illuminated by the illumination system are the same as thecoordinates of the same test colors being irradiated by a referencelight source of equivalent CCT. For CCTs less than 5000K, the referenceilluminants used in the CRT calculation procedure are the SPDs ofblackbody radiators; for CCTs above 5000K, imaginary SPDs calculatedfrom a mathematical model of daylight are used. These reference sourceswere selected to approximate incandescent lamps and daylight,respectively. Daylight generally has an Ra value of nearly 100,incandescent bulbs have an Ra value of about 95, fluorescent lightingtypically has an Ra value of about 70 to 85, while monochromatic lightsources have an Ra value of essentially zero. Light sources for generalillumination applications with an Ra value of less than 50 are generallyconsidered very poor and are typically only used in applications whereeconomic issues preclude other alternatives. The calculation of CIE Ravalues is described more fully in Commission Internationale del'Eclairage. 1995. Technical Report: Method of Measuring and SpecifyingColour Rendering Properties of Light Sources, CIE No. 13.3-1995. Vienna,Austria: Commission Internationale de l'Eclairage, which is incorporatedby reference herein in its entirety for all purposes. In addition to theRa value, a light source can also be evaluated based on a measure of itsability to render seven additional colors R9-R15, which includerealistic colors like red, yellow, green, blue, caucasian skin color(R13), tree leaf green, and asian skin color (R15), respectively. Theability to render the saturated red reference color R9 can be expressedwith the R9 color rendering value (“R9 value”). Light sources canfurther be evaluated by calculating the gamut area index (“GAT”).Connecting the rendered color points from the determination of the CIERa value in two dimensional space will form a gamut area. Gamut areaindex is calculated by dividing the gamut area formed by the lightsource with the gamut area formed by a reference source using the sameset of colors that are used for CRT. GAT uses an Equal Energy Spectrumas the reference source rather than a black body radiator. A gamut areaindex related to a black body radiator (“GAIBB”) can be calculated byusing the gamut area formed by the blackbody radiator at the equivalentCCT to the light source.

The ability of a light source to accurately reproduce color inilluminated objects can be characterized using the metrics described inIES Method for Evaluating Light Source Color Rendition, IlluminatingEngineering Society, Product ID: TM-30-15 (referred to herein as the“TM-30-15 standard”), which is incorporated by reference herein in itsentirety for all purposes. The TM-30-15 standard describes metricsincluding the Fidelity Index (Rf) and the Gamut Index (Rg) that can becalculated based on the color rendition of a light source for 99 colorevaluation samples (“CES”). The 99 CES provide uniform color spacecoverage, are intended to be spectral sensitivity neutral, and providecolor samples that correspond to a variety of real objects. Rf valuesrange from 0 to 100 and indicate the fidelity with which a light sourcerenders colors as compared with a reference illuminant. Rg valuesprovide a measure of the color gamut that the light source providesrelative to a reference illuminant. The range of Rg depends upon the Rfvalue of the light source being tested. The reference illuminant isselected depending on the CCT. For CCT values less than or equal to4500K, Planckian radiation is used. For CCT values greater than or equalto 5500K, CIE Daylight illuminant is used. Between 4500K and 5500K aproportional mix of Planckian radiation and the CIE Daylight illuminantis used, according to the following equation:

${{S_{r,M}\left( {\lambda,T_{t}} \right)} = {{\frac{5500 - T_{t}}{1000}{S_{r,P}\left( {\lambda,T_{t}} \right)}} + {\left( {1 - \frac{5500 - T_{t}}{1000}} \right){S_{r,D}\left( {\lambda,T_{t}} \right)}}}},$

where T_(t) is the CCT value, S_(r,M)(λ, T_(t)) is the proportional mixreference illuminant, S_(r,P)(λ, T_(t)) is Planckian radiation, andS_(r,D)(λ, T_(t)) is the CIE Daylight illuminant.

Circadian illuminance (CLA) is a measure of circadian effective light,spectral irradiance distribution of the light incident at the corneaweighted to reflect the spectral sensitivity of the human circadiansystem as measured by acute melatonin suppression after a one-hourexposure, and CS, which is the effectiveness of the spectrally weightedirradiance at the cornea from threshold (CS=0.1) to saturation (CS=0.7).The values of CLA are scaled such that an incandescent source at 2856K(known as CIE Illuminant A) which produces 1000 lux (visual lux) willproduce 1000 units of circadian lux (CLA). CS values are transformed CLAvalues and correspond to relative melotonian suppression after one hourof light exposure for a 2.3 mm diameter pupil during the mid-point ofmelotonian production. CS is calculated from

${CS} = {{0.7{\left( {1 - \frac{1}{1 + \left( \frac{CLA}{355.7} \right)^{\bigwedge 1.126}}} \right).}}}$

The calculation of CLA is more fully described in Rea et al., “Modellingthe spectral sensitivity of the human circadian system,” LightingResearch and Technology, 2011; 0: 1-12, and Figueiro et al., “Designingwith Circadian Stimulus”, October 2016, LD+A Magazine, IlluminatingEngineering Society of North America, which are incorporated byreference herein in its entirety for all purposes. Figueiro et al.describe that exposure to a CS of 0.3 or greater at the eye, for atleast one hour in the early part of the day, is effective forstimulating the circadian system and is associated with better sleep andimproved behavior and mood.

Equivalent Melanopic Lux (EML) provides a measure of photoreceptiveinput to circadian and neurophysiological light responses in humans, asdescribed in Lucas et al., “Measuring and using light in the melanopsinage.” Trends in Neurosciences, January 2014, Vol. 37, No. 1, pages 1-9,which is incorporated by reference herein in its entirety, including allappendices, for all purposes. Melanopic lux is weighted to aphotopigment with λmax 480 nm with pre-receptoral filtering based on a32 year old standard observer, as described more fully in the AppendixA, Supplementary Data to Lucas et al. (2014), User Guide: IrradianceToolbox (Oxford 18 Oct. 2013), University of Manchester, Lucas Group,which is incorporated by reference herein in its entirety for allpurposes.

Blue Light Hazard (BLH) provides a measure of potential for aphotochemical induced retinal injury that results from radiationexposure. Blue Light Hazard is described in IEC/EN 62471,Photobiological Safety of Lamps and Lamp Systems and Technical ReportIEC/TR 62778: Application of IEC 62471 for the assessment of blue lighthazard to light sources and luminaires, which are incorporated byreference herein in their entirety for all purposes. A BLH factor can beexpressed in (weighted power/lux) in units of μW/cm²/lux.

In some aspects the present disclosure relates to lighting devices andmethods to provide light having particular vision energy and circadianenergy performance. Many figures of merit are known in the art, some ofwhich are described in Ji Hye Oh, Su Ji Yang and Young Rag Do, “Healthy,natural, efficient and tunable lighting: four-package white LEDs foroptimizing the circadian effect, color quality and vision performance,”Light: Science & Applications (2014) 3: e141-e149, which is incorporatedherein in its entirety, including supplementary information, for allpurposes. Luminous efficacy of radiation (“LER”) can be calculated fromthe ratio of the luminous flux to the radiant flux (S(λ)), i.e. thespectral power distribution of the light source being evaluated, withthe following equation:

${{LER}\left( \frac{lm}{W} \right)} = {683\left( \frac{lm}{W} \right){\frac{\int{{V(\lambda)}{S(\lambda)}d\; \lambda}}{\int{{S(\lambda)}d\; \lambda}}.}}$

Circadian efficacy of radiation (“CER”) can be calculated from the ratioof circadian luminous flux to the radiant flux, with the followingequation:

${{CER}\left( \frac{blm}{W} \right)} = {683\left( \frac{blm}{W} \right){\frac{\int{{C(\lambda)}{S(\lambda)}d\; \lambda}}{\int{{S(\lambda)}d\; \lambda}}.}}$

Circadian action factor (“CAF”) can be defined by the ratio of CER toLER, with the following equation:

$\left( \frac{blm}{lm} \right) = {\frac{{CER}\left( \frac{blm}{W} \right)}{{LER}\left( \frac{lm}{W} \right)}.}$

The term “blm” refers to biolumens, units for measuring circadian flux,also known as circadian lumens. The term “lm” refers to visual lumens.V(λ) is the photopic spectral luminous efficiency function and C(λ) isthe circadian spectral sensitivity function. The calculations herein usethe circadian spectral sensitivity function, C(λ), from Gall et al.,Proceedings of the CIE Symposium 2004 on Light and Health: Non-VisualEffects, 30 Sep.-2 Oct. 2004; Vienna, Austria 2004. CIE: Wien, 2004, pp129-132, which is incorporated herein in its entirety for all purposes.By integrating the amount of light (milliwatts) within the circadianspectral sensitivity function and dividing such value by the number ofphotopic lumens, a relative measure of melatonin suppression effects ofa particular light source can be obtained. A scaled relative measuredenoted as melatonin suppressing milliwatts per hundred lumens may beobtained by dividing the photopic lumens by 100. The term “melatoninsuppressing milliwatts per hundred lumens” consistent with the foregoingcalculation method is used throughout this application and theaccompanying figures and tables.

The ability of a light source to provide illumination that allows forthe clinical observation of cyanosis is based upon the light source'sspectral power density in the red portion of the visible spectrum,particularly around 660 nm. The cyanosis observation index (“COI”) isdefined by AS/NZS 1680.2.5 Interior Lighting Part 2.5: Hospital andMedical Tasks, Standards Australia, 1997 which is incorporated byreference herein in its entirety, including all appendices, for allpurposes. COI is applicable for CCTs from about 3300K to about 5500K,and is preferably of a value less than about 3.3. If a light source'soutput around 660 nm is too low a patient's skin color may appear darkerand may be falsely diagnosed as cyanosed. If a light source's output at660 nm is too high, it may mask any cyanosis, and it may not bediagnosed when it is present. COI is a dimensionless number and iscalculated from the spectral power distribution of the light source. TheCOI value is calculated by calculating the color difference betweenblood viewed under the test light source and viewed under the referencelamp (a 4000 K Planckian source) for 50% and 100% oxygen saturation andaveraging the results. The lower the value of COI, the smaller the shiftin color appearance results under illumination by the source underconsideration.

The ability of a light source to accurately reproduce color inilluminated objects can be characterized by the Television LightingConsistency Index (“TLCI-2012” or “TLCI”) value Qa, as described fullyin EBU Tech 3355, Method for the Assessment of the ColorimetricProperties of Luminaires, European Broadcasting Union (“EBU”), Geneva,Switzerland (2014), and EBU Tech 3355-s1, An Introduction toSpectroradiometry, which are incorporated by reference herein in theirentirety, including all appendices, for all purposes. The TLCI comparesthe test light source to a reference luminaire, which is specified to beone whose chromaticity falls on either the Planckian or Daylight locusand having a color temperature which is that of the CCT of the testlight source. If the CCT is less than 3400 K, then a Planckian radiatoris assumed. If the CCT is greater than 5000 K, then a Daylight radiatoris assumed. If the CCT lies between 3400 K and 5000 K, then a mixedilluminant is assumed, being a linear interpolation between Planckian at3400 K and Daylight at 5000 K. Therefore, it is necessary to calculatespectral power distributions for both Planckian and Daylight radiators.The mathematics for both operations is known in the art and is describedmore fully in CIE Technical Report 15:2004, Colorimetry 3rd ed.,International Commission on Illumination (2004), which is incorporatedherein in its entirety for all purposes.

In some exemplary implementations, the present disclosure providessemiconductor light emitting devices 100 that include a plurality of LEDstrings, with each LED string having a recipient luminophoric mediumthat comprises a luminescent material. The LED(s) in each string and theluminophoric medium in each string together emit an unsaturated lighthaving a color point within a color range in the 1931 CIE chromaticitydiagram. A “color range” in the 1931 CIE chromaticity diagram refers toa bounded area defining a group of color coordinates (ccx, ccy).

In some implementations, four LED strings (101A/101B/101C/101D) arepresent in a device 100. One or more of the LED strings can haverecipient luminophoric mediums (102A/102B/102C/102D). In someimplementations, one or more of the luminophoric mediums can be omitted.In certain implementations, the fourth luminophoric medium 102D can beomitted. A first LED string 101A and a first luminophoric medium 102Atogether can emit a first light having a first color point within a bluecolor range. The combination of the first LED string 101A and the firstluminophoric medium 102A are also referred to herein as a “bluechannel.” A second LED string 101B and a second luminophoric medium 102Btogether can emit a second light having a second color point within ared color range. The combination of the second LED string 101A and thesecond luminophoric medium 102A are also referred to herein as a “redchannel.” A third LED string 101C and a third luminophoric medium 102Ctogether can emit a third light having a third color point within agreen color range. The combination of the third LED string 101C and thethird luminophoric medium 102C are also referred to herein as a “greenchannel.” A fourth LED string 101D can be provided for functionalperformance for capability other than white light generation, or canprovide an additional channel within the visible light spectrum tocontribute to white light generation.

The first, second, third, and fourth LED strings 101A/101B/101C/101D canbe provided with independently applied on-state drive currents in orderto tune the intensity of the first, second, third, and fourthunsaturated light produced by each string and luminophoric mediumtogether. By varying the drive currents in a controlled manner, thecolor coordinate (ccx, ccy) of the total light that is emitted from thedevice 100 can be tuned. In some implementations, the device 100 canprovide light at substantially the same color coordinate with differentspectral power distribution profiles, which can result in differentlight characteristics at the same CCT. In some implementations, whitelight can be generated in modes that only produce light from two orthree of the LED strings. In one implementation, white light isgenerated using only the first, second, and third LED strings, i.e. theblue, red, and green channels. In another implementation, white light isgenerated using only the first, second, third, and fourth LED strings,i.e., the blue, red, and green channels, and an additional channel. Insome implementations, only two of the LED strings are producing lightduring the generation of white light, as the other two LED strings arenot necessary to generate white light at the desired color point withthe desired color rendering performance.

FIGS. 4-6 depict suitable color ranges for some implementations of thedisclosure. FIG. 4A depicts a blue color range 301A defined by a lineconnecting the ccx, ccy color coordinates of the infinity point of thePlanckian locus (0.242, 0.24) and (0.12, 0.068), the Planckian locusfrom 4000K and infinite CCT, the constant CCT line of 4000K, the line ofpurples, and the spectral locus. FIG. 4B depicts a red color range 302Adefined by the spectral locus between the constant CCT line of 1600K andthe line of purples, the line of purples, a line connecting the ccx, ccycolor coordinates (0.61, 0.21) and (0.47, 0.28), and the constant CCTline of 1600K. FIG. 4C depicts a green color range 303A defined by theconstant CCT line of 6700K, the Planckian locus, and the spectral locus.It should be understood that any gaps or openings in the describedboundaries for the color ranges 301A, 302A, 303A should be closed withstraight lines to connect adjacent endpoints in order to define a closedboundary for each color range.

In some implementations, suitable color ranges can be narrower thanthose described above. FIG. 5 depicts some suitable color ranges forsome implementations of the disclosure. A blue color range 301B can bedefined by a 60-step MacAdam ellipse at a CCT of 20000K, 40 points belowthe Planckian locus. A red color range 302B can be defined by a 20-stepMacAdam ellipse at a CCT of 1200K, 20 points below the Planckian locus.A green color range 303B shown in FIG. 4D can be defined by a 60-stepMacAdam ellipse centered approximately 65 points above the Planckianlocus at 4500K, the Planckian locus, and the constant CCT line of 6700K.FIG. 6 depicts some further color ranges suitable for someimplementations of the disclosure. A blue color range 301C is defined bya polygonal region on the 1931 CIE Chromaticity Diagram defined by thefollowing ccx, ccy color coordinates: (0.22, 0.14), (0.19, 0.17), (0.26,0.26), (0.28, 0.23). A red color range 302C is defined by a polygonalregion on the 1931 CIE Chromaticity Diagram defined by the followingccx, ccy color coordinates: (0.53, 0.41), (0.59, 0.39), (0.63, 0.29),(0.58, 0.30).

In some implementations, the LEDs in the first, second, third and fourthLED strings can be LEDs with peak emission wavelengths at or below about535 nm. In some implementations, the LEDs emit light with peak emissionwavelengths between about 360 nm and about 535 nm. In someimplementations, the LEDs in the first, second, third and fourth LEDstrings can be formed from InGaN semiconductor materials. In somepreferred implementations, the first, second, and third LED strings canhave LEDs having a peak wavelength between about 405 nm and about 485nm. The LEDs used in the first, second, third, and fourth LED stringsmay have full-width half-maximum wavelength ranges of between about 10nm and about 30 nm. In some preferred implementations, the first,second, and third LED strings can include one or more LUXEON Z ColorLine royal blue LEDs (product code LXZ1-PR01) of color bin codes 3, 4,5, or 6 or one or more LUXEON Z Color Line blue LEDs (LXZ1-PB01) ofcolor bin code 1 or 2 (Lumileds Holding B.V., Amsterdam, Netherlands).Similar LEDs from other manufacturers such as OSRAM GmbH and Cree, Inc.could also be used, provided they have peak emission and full-widthhalf-maximum wavelengths of the appropriate values.

In implementations utilizing LEDs that emit substantially saturatedlight at wavelengths between about 360 nm and about 535 nm, the device100 can include suitable recipient luminophoric mediums for each LED inorder to produce light having color points within the suitable bluecolor ranges 301A-C, red color ranges 302A-C, and green color ranges303A-B described herein. The light emitted by each LED string, i.e., thelight emitted from the LED(s) and associated recipient luminophoricmedium together, can have a spectral power distribution (“SPD”) havingspectral power with ratios of power across the visible wavelengthspectrum from about 380 nm to about 780 nm. While not wishing to bebound by any particular theory, it is speculated that the use of suchLEDs in combination with recipient luminophoric mediums to createunsaturated light within the suitable color ranges 301A-C, 302A-C, and303A-B, provides for improved color rendering performance for whitelight across a predetermined range of CCTs from a single device 100.Some suitable ranges for spectral power distribution ratios of the lightemitted by the four LED strings (101A/101B/101C) and recipientluminophoric mediums (102A/102B/102C), if provided, together are shownin Tables 1, 2, 3, and 4. The Tables 1, 2, 3, and 4 show the ratios ofspectral power within wavelength ranges, with an arbitrary referencewavelength range selected for each color range and normalized to a valueof 100.0. Tables 1 and 2 show suitable minimum and maximum values forthe spectral intensities within various ranges relative to thenormalized range with a value of 100.0, for the color points within theblue, green, and red color ranges. While not wishing to be bound by anyparticular theory, it is speculated that because the spectral powerdistributions for generated light with color points within the red,blue, and green color ranges contains higher spectral intensity acrossvisible wavelengths as compared to lighting apparatuses and methods thatutilize more saturated colors, this allows for improved color renderingfor test colors other than R1-R8.

TABLE 1 Spectral Power Distribution for Wavelength Ranges (nm) 380-420420-460 461-500 501-540 541-580 581-620 621-660 661-700 701-741 741-780Blue minimum 0.3 100.0 20.9 15.2 25.3 26.3 15.4 5.9 2.3 1.0 Blue maximum8.1 100.0 196.1 35.6 40.5 70.0 80.2 20.4 7.8 2.3 Red minimum 0.0 2.1 2.01.4 8.7 48.5 100.0 1.8 0.5 0.3 Red maximum 14.8 15. 6.7 12.2 20.5 102.8100.0 74.3 29.5 9.0 Green minimum 0.2 100.0 112.7 306.2 395.1 318.2245.0 138.8 52.6 15.9 Green maximum 130.6 100.0 534.7 6748.6 10704.113855.8 15041.2 9802.9 3778.6 1127.3

TABLE 2 Spectral Power Distribution for Wavelength Ranges (nm) 380-500501-600 601-700 701-780 Blue minimum 100.0 27.0 24.8 1.1 Blue maximum100.0 65.1 46.4 6.8 Red minimum 17.4 8.9 100.0 1.1 Red maximum 3.3 24.8100.0 18.1 Green minimum 100.0 279.0 170.8 14.6 Green maximum 100.02313.6 2211.6 270.7

In some implementations, the green channel can have certain spectralpower distributions. Table 3 shows the ratios of spectral power withinwavelength ranges, with an arbitrary reference wavelength range selectedfor the green color range and normalized to a value of 100.0, for agreen channel that may be used in some implementations of thedisclosure. The exemplary Green Channel 1 has a ccx, ccy colorcoordinate of (0.3263, 0.5403) and a dominant wavelength ofapproximately 554 nm. The exemplary Green Channel 2 has a ccx, ccy colorcoordinate of (0.4482, 0.5258) and a dominant wavelength ofapproximately 573 nm. The exemplary Green Channel 3 has a ccx, ccy colorcoordinate of (0.5108, 0.4708) and a dominant wavelength ofapproximately 582 nm. In certain implementations, the green channel canhave a spectral power distribution with spectral power in one or more ofthe wavelength ranges other than the reference wavelength rangeincreased or decreased within 30% greater or less, within 20% greater orless, within 10% greater or less, or within 5% greater or less than thevalues shown in Table 3.

In some implementations, the red channel can have certain spectral powerdistributions. Tables 3 and 4 show the ratios of spectral power withinwavelength ranges, with an arbitrary reference wavelength range selectedfor the red color range and normalized to a value of 100.0, for a redchannel that may be used in some implementations of the disclosure. Theexemplary Red Channel 1 has a ccx, ccy color coordinate of (0.5735,0.3007) and a dominant wavelength of approximately 641 nm. The exemplaryRed Channel 2 has a ccx, ccy color coordinate of (0.5842, 0.3112) and adominant wavelength of approximately 625 nm. In certain implementations,the red channel can have a spectral power distribution with spectralpower in one or more of the wavelength ranges other than the referencewavelength range increased or decreased within 30% greater or less,within 20% greater or less, within 10% greater or less, or within 5%greater or less than the values shown in Tables 3 and 4.

In some implementations, the blue channel can have certain spectralpower distributions. Tables 3 and 4 show the ratios of spectral powerwithin wavelength ranges, with an arbitrary reference wavelength rangeselected for the blue color range and normalized to a value of 100.0,for a blue channel that may be used in some implementations of thedisclosure. The exemplary Blue Channel 1 has a ccx, ccy color coordinateof (0.252, 0.223) and a dominant wavelength of approximately 470 nm.Exemplary Blue Channel 2 has a ccx, ccy color coordinate of (0.2625,0.1763) and a dominant wavelength of approximately 381 nm. In certainimplementations, the blue channel can have a spectral power distributionwith spectral power in one or more of the wavelength ranges other thanthe reference wavelength range increased or decreased within 30% greateror less, within 20% greater or less, within 10% greater or less, orwithin 5% greater or less than the values shown in Tables 3 and 4.

TABLE 3 Spectral Power Distribution for Wavelength Ranges (nm) ExemplaryColor Channels 380-400 401-420 421-440 441-460 461-480 481-500 501-520521-540 541-560 561-580 581-600 Blue Channel 1 0.3 0.7 11.4 100 70.727.9 23.5 25.1 24.6 22.3 21.0 Red Channel 1 0.1 0.1 0.7 4.5 4.9 3.5 6.711.6 17.6 30.0 48.9 Green Channel 1 0.6 0.5 2.4 14.0 21.6 63.4 97.1 99.5100.0 89.1 71.9 Green Channel 2 0.4 1.5 1.6 0.5 1.0 10.0 53.1 93.5 100.093.5 84.5 Green Channel 3 0.0 0.0 0.1 1.2 2.3 3.3 23.1 51.6 64.5 67.573.5 Exemplary Color Channels 601-620 621-640 641-660 661-680 681-700701-720 721-740 741-760 761-780 781-800 Blue Channel 1 21.2 20.9 18.113.4 8.7 5.2 3.1 1.9 1.3 0.0 Red Channel 1 67.9 93.5 100.0 66.0 33.716.5 7.6 3.2 1.5 0.0 Green Channel 1 57.8 54.1 48.6 31.0 16.1 8.1 3.91.8 1.1 0.0 Green Channel 2 77.3 72.0 62.7 47.5 31.7 19.2 11.0 6.0 3.10.0 Green Channel 3 89.3 100.0 91.3 70.0 47.1 28.8 16.6 9.1 4.8 0.0

TABLE 4 Spectral Power Distribution for Wavelength Ranges (nm) ExemplaryColor Channels 380-420 420-460 461-500 501-540 541-580 581-620 621-660661-700 701-741 741-780 Blue Channel 2 0.4 100.0 20.9 15.2 25.3 26.325.1 13.9 5.2 1.6 Red Channel 2 9.2 8.6 1.0 4.6 11.0 46.5 100.0 75.529.8 8.5

In some implementations, the semiconductor light emitting devices of thepresent disclosure can include first, second, and third LED strings101A/101B/101C that generate the red, blue, and green channels describedelsewhere herein in combination with luminophoric mediums102A/102B/102C. In certain implementations, the first, second, and thirdLED strings can provide broad-range, spectrally rich high CRI whitelight, which can enable the use of an application-specific fourth LEDstring. The application-specific fourth LED string can contribute to thecolor-rendering of white light generated by the other three LED strings,or the fourth LED string can be operated in a separate mode when theother three LED strings are not generating light, or the fourth LEDstring can be operated simultaneously with the other three LED stringsbut can generate wavelengths unrelated to white light. In someimplementations, a fourth LED string can be provide in the semiconductorlight emitting devices of the disclosure, with the fourth LED stringincluding diodes that can have emissions driven by the same electroniccircuitry and control systems as the diodes of the first, second, andthird LED strings. In certain implementations, the semiconductor lightemitting devices can further include a fourth LED string that comprisesone or more of 380-420 nm violet saturated LEDs, 200-280 nm UVCsaturated LEDs, 850-940 nm near-IR saturated LEDs, 580-620 nmamber-orange/red saturated LEDs, 460-490 nm long-blue saturated LEDs, orany other type of LEDs with the desired application-specific wavelengthemissions. In certain implementations, each diode in the fourth LEDstring can be provided with an associated luminophoric medium so that adesired combined emission of unsaturated light can be provided.

Blends of luminescent materials can be used in luminophoric mediums(102A/102B/102C/102D) to create luminophoric mediums having the desiredsaturated color points when excited by their respective LED strings(101A/101B/101C/101D) including luminescent materials such as thosedisclosed in co-pending application PCT/US2016/015318 filed Jan. 28,2016, entitled “Compositions for LED Light Conversions”, the entirety ofwhich is hereby incorporated by this reference as if fully set forthherein. Traditionally, a desired combined output light can be generatedalong a tie line between the LED string output light color point and thesaturated color point of the associated recipient luminophoric medium byutilizing different ratios of total luminescent material to theencapsulant material in which it is incorporated. Increasing the amountof luminescent material in the optical path will shift the output lightcolor point towards the saturated color point of the luminophoricmedium. In some instances, the desired saturated color point of arecipient luminophoric medium can be achieved by blending two or moreluminescent materials in a ratio. The appropriate ratio to achieve thedesired saturated color point can be determined via methods known in theart. Generally speaking, any blend of luminescent materials can betreated as if it were a single luminescent material, thus the ratio ofluminescent materials in the blend can be adjusted to continue to meet atarget CIE value for LED strings having different peak emissionwavelengths. Luminescent materials can be tuned for the desiredexcitation in response to the selected LEDs used in the LED strings(101A/101B/101C/101D), which may have different peak emissionwavelengths within the range of from about 360 nm to about 535 nm.Suitable methods for tuning the response of luminescent materials areknown in the art and may include altering the concentrations of dopantswithin a phosphor, for example. In some implementations of the presentdisclosure, luminophoric mediums can be provided with combinations oftwo types of luminescent materials. The first type of luminescentmaterial emits light at a peak emission between about 515 nm and about590 nm in response to the associated LED string emission. The secondtype of luminescent material emits at a peak emission between about 590nm and about 700 nm in response to the associated LED string emission.In some instances, the luminophoric mediums disclosed herein can beformed from a combination of at least one luminescent material of thefirst and second types described in this paragraph. In implementations,the luminescent materials of the first type can emit light at a peakemission at about 515 nm, 525 nm, 530 nm, 535 nm, 540 nm, 545 nm, 550nm, 555 nm, 560 nm, 565 nm, 570 nm, 575 nm, 580 nm, 585 nm, or 590 nm inresponse to the associated LED string emission. In preferredimplementations, the luminescent materials of the first type can emitlight at a peak emission between about 520 nm to about 555 nm. Inimplementations, the luminescent materials of the second type can emitlight at a peak emission at about 590 nm, about 595 nm, 600 nm, 605 nm,610 nm, 615 nm, 620 nm, 625 nm, 630 nm, 635 nm, 640 nm, 645 nm, 650 nm,655 nm, 670 nm, 675 nm, 680 nm, 685 nm, 690 nm, 695 nm, or 700 nm inresponse to the associated LED string emission. In preferredimplementations, the luminescent materials of the first type can emitlight at a peak emission between about 600 nm to about 670 nm. Someexemplary luminescent materials of the first and second type aredisclosed elsewhere herein and referred to as Compositions A-F. Table 5shows aspects of some exemplar luminescent materials and properties:

TABLE 5 Emission Emission FWHM Exemplary Density Peak FWHM Peak RangeRange Designator Material(s) (g/mL) (nm) (nm) (nm) (nm) CompositionLuag: Cerium doped lutetium 6.73 535 95 530-540  90-100 “A” aluminumgarnet (Lu₃Al₅O₁₂) Composition Yag: Cerium doped yttrium 4.7 550 110545-555 105-115 “B” aluminum garnet (Y₃Al₅O₁₂) Composition a 650 nm-peakwavelength 3.1 650 90 645-655 85-95 “C” emission phosphor: Europiumdoped calcium aluminum silica nitride (CaAlSiN₃) Composition a 525nm-peak wavelength 3.1 525 60 520-530 55-65 “D” emission phosphor: GBAM:BaMgAl₁₀O₁₇: Eu Composition a 630 nm-peak wavelength 5.1 630 40 625-63535-45 “E” emission quantum dot: any semiconductor quantum dot materialof appropriate size for desired emission wavelengths Composition a 610nm-peak wavelength 5.1 610 40 605-615 35-45 “F” emission quantum dot:any semiconductor quantum dot material of appropriate size for desiredemission wavelengths

Blends of Compositions A-F can be used in luminophoric mediums(102A/102B/102C/102D) to create luminophoric mediums having the desiredsaturated color points when excited by their respective LED strings(101A/101B/101C/101D). In some implementations, one or more blends ofone or more of Compositions A-F can be used to produce luminophoricmediums (102A/102B/102C/102D). In some preferred implementations, one ormore of Compositions A, B, and D and one or more of Compositions C, E,and F can be combined to produce luminophoric mediums(102A/102B/102C/102D). In some preferred implementations, theencapsulant for luminophoric mediums (102A/102B/102C/102D) comprises amatrix material having density of about 1.1 mg/mm³ and refractive indexof about 1.545 or from about 1.4 to about 1.6. In some implementations,Composition A can have a refractive index of about 1.82 and a particlesize from about 18 micrometers to about 40 micrometers. In someimplementations, Composition B can have a refractive index of about 1.84and a particle size from about 13 micrometers to about 30 micrometers.In some implementations, Composition C can have a refractive index ofabout 1.8 and a particle size from about 10 micrometers to about 15micrometers. In some implementations, Composition D can have arefractive index of about 1.8 and a particle size from about 10micrometers to about 15 micrometers. Suitable phosphor materials forCompositions A, B, C, and D are commercially available from phosphormanufacturers such as Mitsubishi Chemical Holdings Corporation (Tokyo,Japan), Intematix Corporation (Fremont, Calif.), EMD PerformanceMaterials of Merck KGaA (Darmstadt, Germany), and PhosphorTechCorporation (Kennesaw, Ga.).

In some applications, it can be desirable to provide white light havingspectral power in the violet or ultraviolet spectrum between 380 nm-420nm. For example, some commercial textiles are provided with brighteningagents that are excited by violet or ultraviolet wavelengths in order toprovide products that appear whiter or more vibrant. Further, somedetergents are provided with such brightening agents, such that clothingmay appear duller under light that lacks violet or ultravioletwavelengths to induce excitation and the desired color appearance to anobserver. Accordingly, in some implementations of the disclosure,devices are provided having one or more LEDs in the violet orultraviolet spectrum in order to contribute those wavelengths to thefinal spectrum of generated white light. This can produce desirableeffects in some settings, such as making clothing or other textilesappear more white or vibrant.

In some aspects, the present disclosure provides semiconductor lightemitting devices capable to producing tunable white light through arange of CCT values. In some implementations, devices of the presentdisclosure can output white light at color points along a predeterminedpath within a 7-step MacAdam ellipse around any point on the black bodylocus having a correlated color temperature between 1800K and 10000K. Insome implementations, the semiconductor light emitting devices cancomprise first, second, and third LED strings, with each LED stringcomprising one or more LEDs having an associated luminophoric medium,wherein the first, second, and third LED strings together with theirassociated luminophoric mediums can comprise red, blue, and greenchannels respectively, producing first, second, and third unsaturatedcolor points within red, blue, and green regions on the 1931 CIEChromaticity diagram, respectively, and a control circuit can beconfigured to adjust a fourth color point of a fourth unsaturated lightthat results from a combination of the first, second, and thirdunsaturated light, with the fourth color point falls within a 7-stepMacAdam ellipse around any point on the black body locus having acorrelated color temperature between 1800K and 10000K. In someimplementations the device further comprises a fourth LED stringcomprising one or more LEDs. In some implementations the LEDs of thefourth LED string comprise a type of LED selected from 380-420 nm violetsaturated LEDs, 200-280 nm UVC saturated LEDs, 850-940 nm near-IRsaturated LEDs, 580-620 nm amber-orange/red saturated LEDs, and 460-490nm long-blue saturated LEDs. In certain implementations, the LEDs of thefourth LED string comprise 380-420 nm violet saturated LEDs. In otherimplementations, the LEDs of the fourth LED string comprise 200-280 nmUVC saturated LEDs. In further implementations, the LEDs of the fourthLED string comprise 850-940 nm near-IR saturated LEDs. In yet furtherimplementations, the LEDs of the fourth LED string comprise 580-620 nmamber-orange/red saturated LEDs. In certain implementations, the controlcircuit is further configured to adjust a sixth color point of a sixthunsaturated light that results from a combination of the first, second,and third unsaturated light and a fifth saturated light generated by thefourth LED string, with the sixth color point falling within a 7-stepMacAdam ellipse around any point on the black body locus having acorrelated color temperature between 1800K and 10000K. In someimplementations, the control circuit is configured to provide twooperating modes comprise a first operating mode that generates lightonly using the blue, red, and green channels and a second operating modethat generates light using the blue, red, and green channels and thefourth LED string. In some implementations, the control circuit isconfigured to switch between the first operating mode and the secondoperating mode to provide the fourth unsaturated light and the sixthunsaturated light having substantially the same ccx, ccy coordinates onthe 1931 CIE Chromaticity Diagram. In some implementations, the fourthunsaturated light and the sixth unsaturated light have color pointswithin about 1.0 standard deviations of color matching (SDCM). In someimplementations, the fourth unsaturated light and the sixth unsaturatedlight have color points within about 0.5 standard deviations of colormatching (SDCM). In certain implementations, the sixth unsaturated lighthas improved color-rendering characteristics in comparison to the fourthunsaturated light. In certain implementations, the improvedcolor-rendering characteristics of the sixth unsaturated light incomparison to the fourth unsaturated light is one or more of Ra, R9, Rf,and Rg. In some implementations, the devices can be configured togenerate the fourth or sixth unsaturated light corresponding to aplurality of points along a predefined path with the light generated ateach point having light with BLH factor less than 0.05 μW/cm²/lux. Insome implementations, the devices can be configured to generate thefourth or sixth unsaturated light corresponding to a plurality of pointsalong a predefined path with the light generated at each point havinglight with one or more of BLH factor less than or equal to about 0.01along points with correlated color temperature below about 2100K, BLHfactor less than or equal to about 0.015 along points with correlatedcolor temperature below about 2400K, BLH factor less than or equal toabout 0.025 along points with correlated color temperature below about3000K, BLH factor less than or equal to about 0.05 along points withcorrelated color temperature below about 4000K, and BLH factor less thanor equal to about 0.060 along points with correlated color temperaturebelow about 6500K. In some implementations, the devices can beconfigured to generate the fourth or sixth unsaturated lightcorresponding to a plurality of points along a predefined path with thelight generated at each point having light with the ratio of the EML tothe BLH factor being greater than or equal to about 15, greater than orequal to about 20, greater than or equal to about 21, greater than orequal to about 22, greater than or equal to about 23, greater than orequal to about 24, greater than or equal to about 25, greater than orequal to about 26, greater than or equal to about 27, greater than orequal to about 28, greater than or equal to about 29, greater than orequal to about 30, greater than or equal to about 35, or greater than orequal to about 40. Providing a higher ratio of the EML to the BLH factorcan be advantageous to provide light that provides desired biologicalimpacts but does not have as much potential for photochemical inducedinjuries to the retina or skin.

In some aspects, the present disclosure provides methods of generatingwhite light, the methods comprising providing first, second, and thirdLED strings, with each LED string comprising one or more LEDs having anassociated luminophoric medium, providing a fourth LED string, whereinthe first, second, and third LED strings together with their associatedluminophoric mediums comprise red, blue, and green channelsrespectively, producing first, second, and third unsaturated light withcolor points within red, blue, and green regions on the 1931 CIEChromaticity diagram, respectively, providing a control circuitconfigured to adjust a fourth color point of a fourth unsaturated lightthat results from a combination of the first, second, and third,unsaturated light, with the fourth color point falls within a 7-stepMacAdam ellipse around any point on the black body locus having acorrelated color temperature between 1800K and 10000K, wherein thecontrol circuit is further configured to adjust a sixth color point of asixth unsaturated light that results from a combination of the first,second, and third unsaturated light and a fifth saturated light from thefourth LED string, generating light in a first operating mode with twoor more of the first, second, and third unsaturated light by combiningthe two or more generated unsaturated lights to create the fourthunsaturated light, and generating light in a second operating mode withtwo or more of the first, second, and third unsaturated light and thefifth saturated light by combining the two or more generatedunsaturated/saturated light to create the sixth unsaturated light. Insome implementations, the LEDs of the fourth LED string comprise a typeof LED selected from 380-420 nm violet saturated LEDs, 200-280 nm UVCsaturated LEDs, 850-940 nm near-IR saturated LEDs, 580-620 nmamber-orange/red saturated LEDs, and 460-490 nm long-blue saturatedLEDs. In some implementations, the LEDs of the fourth LED stringcomprise 380-420 nm violet saturated LEDs. In some implementations, theLEDs of the fourth LED string comprise 200-280 nm UVC saturated LEDs. Insome implementations, the LEDs of the fourth LED string comprise 850-940nm near-IR saturated LEDs. In some implementations, the LEDs of thefourth LED string comprise 580-620 nm amber-orange/red saturated LEDs.In some implementations, the control circuit is configured to switchbetween the first operating mode and the second operating mode toprovide the fourth unsaturated light and the sixth unsaturated lighthaving substantially the same ccx, ccy coordinates on the 1931 CIEChromaticity Diagram. In some implementations, the fourth unsaturatedlight and the sixth unsaturated light have color points within about 1.0standard deviations of color matching (SDCM). In some implementations,the fourth unsaturated light and the sixth unsaturated light have colorpoints within about 0.5 standard deviations of color matching (SDCM). Insome implementations, the sixth unsaturated light has improvedcolor-rendering performance in comparison to the fourth unsaturatedlight in one or more of Ra, R9, Rf, and Rg.

EXAMPLES General Simulation Method.

Devices having four LED strings with particular color points weresimulated. For each device, LED strings and recipient luminophoricmediums with particular emissions were selected, and then white lightrendering capabilities were calculated for a select number ofrepresentative points on or near the Planckian locus between about 1800Kand 10000K. Ra, R9, R13, R15, LER, Rf, Rg, CLA, CS, EML, BLH factor,CAF, CER, COI, and circadian performance values were calculated at eachrepresentative point.

The calculations were performed with Scilab (Scilab Enterprises,Versailles, France), LightTools (Synopsis, Inc., Mountain View, Calif.),and custom software created using Python (Python Software Foundation,Beaverton, Oreg.). Each LED string was simulated with an LED emissionspectrum and excitation and emission spectra of luminophoric medium(s).For luminophoric mediums comprising phosphors, the simulations alsoincluded the absorption spectrum and particle size of phosphorparticles. The LED strings generating combined emissions within blue,green, and red color regions were prepared using spectra of a LUXEON ZColor Line royal blue LED (product code LXZ1-PR01) of color bin codes 3,4, 5, or 6 or a LUXEON Z Color Line blue LED (LXZ1-PB01) of color bincode 1 or 2 (Lumileds Holding B.V., Amsterdam, Netherlands). SimilarLEDs from other manufacturers such as OSRAM GmbH and Cree, Inc. couldalso be used.

The emission, excitation and absorption curves are available fromcommercially available phosphor manufacturers such as MitsubishiChemical Holdings Corporation (Tokyo, Japan), Intematix Corporation(Fremont, Calif.), EMD Performance Materials of Merck KGaA (Darmstadt,Germany), and PhosphorTech Corporation (Kennesaw, Ga.). The luminophoricmediums used in the LED strings were combinations of one or more ofCompositions A, B, and D and one or more of Compositions C, E, and F asdescribed more fully elsewhere herein. Those of skill in the artappreciate that various combinations of LEDs and luminescent blends canbe combined to generate combined emissions with desired color points onthe 1931 CIE chromaticity diagram and the desired spectral powerdistributions.

Example 1

A semiconductor light emitting device was simulated having four LEDstrings. A first LED string is driven by a blue LED having peak emissionwavelength of approximately 450 nm to approximately 455 nm, utilizes arecipient luminophoric medium, and generates a combined emission of ablue channel having the characteristics of Blue Channel 1 as describedabove and shown in Table 3. A second LED string is driven by a blue LEDhaving peak emission wavelength of approximately 450 nm to approximately455 nm, utilizes a recipient luminophoric medium, and generates acombined emission of a red channel having the characteristics of RedChannel 1 as described above and shown in Table 3. A third LED string isdriven by a blue LED having peak emission wavelength of approximately450 nm to approximately 455 nm, utilizes a recipient luminophoricmedium, and generates a combined emission of a green color channelhaving the characteristics of Green Channel 1 as described above andshown in Table 3. A fourth LED string is a violet LED having a peakemission wavelength of approximately 380 nm.

FIGS. 7A-7F shows light-rendering characteristics of the device for arepresentative selection of white light color points near the Planckianlocus. FIGS. 7A-7B show data for white light color points generatedusing only the first, second, and third LED strings. FIGS. 7C-7D showdata for white light color points generated using all four LED strings.FIGS. 7E-7F show performance comparison between white light color pointsgenerated at similar approximate CCT values under operating modes usingthree or four LED strings.

Example 2

A semiconductor light emitting device was simulated having four LEDstrings. A first LED string is driven by a blue LED having peak emissionwavelength of approximately 450 nm to approximately 455 nm, utilizes arecipient luminophoric medium, and generates a combined emission of ablue channel having the characteristics of Blue Channel 1 as describedabove and shown in Table 3. A second LED string is driven by a blue LEDhaving peak emission wavelength of approximately 450 nm to approximately455 nm, utilizes a recipient luminophoric medium, and generates acombined emission of a red channel having the characteristics of RedChannel 1 as described above and shown in Table 3. A third LED string isdriven by a blue LED having peak emission wavelength of approximately450 nm to approximately 455 nm, utilizes a recipient luminophoricmedium, and generates a combined emission of a green color channelhaving the characteristics of Green Channel 1 as described above andshown in Table 3. A fourth LED string is a violet LED having a peakemission wavelength of approximately 400 nm.

FIGS. 8A-8F shows light-rendering characteristics of the device for arepresentative selection of white light color points near the Planckianlocus. FIGS. 8A-8B show data for white light color points generatedusing only the first, second, and third LED strings. FIGS. 8C-8D showdata for white light color points generated using all four LED strings.FIGS. 8E-8F show performance comparison between white light color pointsgenerated at similar approximate CCT values under operating modes usingthree or four LED strings.

Example 3

A semiconductor light emitting device was simulated having four LEDstrings. A first LED string is driven by a blue LED having peak emissionwavelength of approximately 450 nm to approximately 455 nm, utilizes arecipient luminophoric medium, and generates a combined emission of ablue channel having the characteristics of Blue Channel 1 as describedabove and shown in Table 3. A second LED string is driven by a blue LEDhaving peak emission wavelength of approximately 450 nm to approximately455 nm, utilizes a recipient luminophoric medium, and generates acombined emission of a red channel having the characteristics of RedChannel 1 as described above and shown in Table 3. A third LED string isdriven by a blue LED having peak emission wavelength of approximately450 nm to approximately 455 nm, utilizes a recipient luminophoricmedium, and generates a combined emission of a green color channelhaving the characteristics of Green Channel 1 as described above andshown in Table 3. A fourth LED string is a violet LED having a peakemission wavelength of approximately 420 nm.

FIGS. 9A-9F shows light-rendering characteristics of the device for arepresentative selection of white light color points near the Planckianlocus. FIGS. 9A-9B show data for white light color points generatedusing only the first, second, and third LED strings. FIGS. 9C-9D showdata for white light color points generated using all four LED strings.FIGS. 9E-9F show performance comparison between white light color pointsgenerated at similar approximate CCT values under operating modes usingthree or four LED strings.

Example 4

A semiconductor light emitting device can be formed from four LEDstrings. A first LED string is driven by a blue LED having peak emissionwavelength of approximately 450 nm to approximately 455 nm, utilizes arecipient luminophoric medium, and generates a combined emission of ablue channel having the characteristics of Blue Channel 1 as describedabove and shown in Table 3. A second LED string is driven by a blue LEDhaving peak emission wavelength of approximately 450 nm to approximately455 nm, utilizes a recipient luminophoric medium, and generates acombined emission of a red channel having the characteristics of RedChannel 1 as described above and shown in Table 3. A third LED string isdriven by a blue LED having peak emission wavelength of approximately450 nm to approximately 455 nm, utilizes a recipient luminophoricmedium, and generates a combined emission of a green color channelhaving the characteristics of Green Channel 1 as described above andshown in Table 3.

A fourth LED string can be a LED string designed to provide functionalperformance for capability other than white light generation. The fourthLED string can be a 200-280 nm UVC saturated LED string to providesterilization capabilities. This generated radiation is non-visible, andmay be used in conjunction with the other visible channels or as analternative mode for hospital rooms or other care facilities. Sensors orother data inputs can verify that the illuminated area is unoccupiedduring a sterilization process using the UVC light.

Example 5

A semiconductor light emitting device can be formed from four LEDstrings. A first LED string is driven by a blue LED having peak emissionwavelength of approximately 450 nm to approximately 455 nm, utilizes arecipient luminophoric medium, and generates a combined emission of ablue channel having the characteristics of Blue Channel 1 as describedabove and shown in Table 3. A second LED string is driven by a blue LEDhaving peak emission wavelength of approximately 450 nm to approximately455 nm, utilizes a recipient luminophoric medium, and generates acombined emission of a red channel having the characteristics of RedChannel 1 as described above and shown in Table 3. A third LED string isdriven by a blue LED having peak emission wavelength of approximately450 nm to approximately 455 nm, utilizes a recipient luminophoricmedium, and generates a combined emission of a green color channelhaving the characteristics of Green Channel 1 as described above andshown in Table 3.

A fourth LED string can be a LED string designed to provide functionalperformance for capability other than white light generation. The fourthLED string can be an 850-940 nm near IR saturated LED to provide “nightvision” capabilities for security cameras. The near IR radiation isnon-visible, and may be used in conjunction with the other visiblechannels or as an alternative mode for lights-out observation of securedfacilities with IR cameras.

Example 6

A semiconductor light emitting device can be formed from four LEDstrings. A first LED string is driven by a blue LED having peak emissionwavelength of approximately 450 nm to approximately 455 nm, utilizes arecipient luminophoric medium, and generates a combined emission of ablue channel having the characteristics of Blue Channel 1 as describedabove and shown in Table 3. A second LED string is driven by a blue LEDhaving peak emission wavelength of approximately 450 nm to approximately455 nm, utilizes a recipient luminophoric medium, and generates acombined emission of a red channel having the characteristics of RedChannel 1 as described above and shown in Table 3. A third LED string isdriven by a blue LED having peak emission wavelength of approximately450 nm to approximately 455 nm, utilizes a recipient luminophoricmedium, and generates a combined emission of a green color channelhaving the characteristics of Green Channel 1 as described above andshown in Table 3.

A fourth LED string can be a LED string designed to provide functionalperformance for capability other than white light generation. The fourthLED string can be a 580-620 nm amber-orange/red saturated LED to providea “night light” mode for assisted care facilities, hospital bathrooms,or nurseries. By not stimulating any of the Circadian-activewavelengths, amber or red/orange light is less likely to disrupt sleeplevels. These wavelengths are close enough to the peak eye response toallow for reasonable visual acuity for tasks like getting to/from abathroom, or changing a baby's diaper. The amber-orange/red color can beused in conjunction with the other three channels or may be used in analternative illumination mode.

Example 7

A semiconductor light emitting device can be formed from four LEDstrings. A first LED string is driven by a blue LED having peak emissionwavelength of approximately 450 nm to approximately 455 nm, utilizes arecipient luminophoric medium, and generates a combined emission of ablue channel having the characteristics of Blue Channel 1 as describedabove and shown in Table 3. A second LED string is driven by a blue LEDhaving peak emission wavelength of approximately 450 nm to approximately455 nm, utilizes a recipient luminophoric medium, and generates acombined emission of a red channel having the characteristics of RedChannel 1 as described above and shown in Table 3. A third LED string isdriven by a blue LED having peak emission wavelength of approximately450 nm to approximately 455 nm, utilizes a recipient luminophoricmedium, and generates a combined emission of a green color channelhaving the characteristics of Green Channel 1 as described above andshown in Table 3.

A fourth LED string can be a LED string designed to provide functionalperformance for capability other than white light generation. The fourthLED string can be a 460-490 nm long-blue saturated LED to provide abilirubin-therapy mode to a general illumination system. This eliminatesthe need for a specific lamp for the purpose in addition togeneral-purpose white lighting. This would allow for physicians toevaluate the infant in situ, under high color quality white light, andreturn the infant to 460-490 nm phototherapy without having to move theinfant from one location to another. The saturated long-blue channelcould provide color rendering benefits when used in conjunction with theother three channels in a white light mode.

Those of ordinary skill in the art will appreciate that a variety ofmaterials can be used in the manufacturing of the components in thedevices and systems disclosed herein. Any suitable structure and/ormaterial can be used for the various features described herein, and askilled artisan will be able to select an appropriate structures andmaterials based on various considerations, including the intended use ofthe systems disclosed herein, the intended arena within which they willbe used, and the equipment and/or accessories with which they areintended to be used, among other considerations. Conventional polymeric,metal-polymer composites, ceramics, and metal materials are suitable foruse in the various components. Materials hereinafter discovered and/ordeveloped that are determined to be suitable for use in the features andelements described herein would also be considered acceptable.

When ranges are used herein for physical properties, such as molecularweight, or chemical properties, such as chemical formulae, allcombinations, and subcombinations of ranges for specific exemplartherein are intended to be included.

The disclosures of each patent, patent application, and publicationcited or described in this document are hereby incorporated herein byreference, in its entirety.

Those of ordinary skill in the art will appreciate that numerous changesand modifications can be made to the exemplars of the disclosure andthat such changes and modifications can be made without departing fromthe spirit of the disclosure. It is, therefore, intended that theappended claims cover all such equivalent variations as fall within thetrue spirit and scope of the disclosure.

What is claimed:
 1. A semiconductor light emitting device comprising:first, second, and third LED strings, with each LED string comprisingone or more LEDs having an associated luminophoric medium; wherein thefirst, second, and third LED strings together with their associatedluminophoric mediums can comprise red, blue, and green channelsrespectively, producing first, second, and third unsaturated colorpoints within red, blue, and green regions on the 1931 CIE Chromaticitydiagram, respectively; a control circuit can be configured to adjust afourth color point of a fourth unsaturated light that results from acombination of the first, second, and third unsaturated light, with thefourth color point falls within a 7-step MacAdam ellipse around anypoint on the black body locus having a correlated color temperaturebetween 1800K and 10000K.
 2. The semiconductor light emitting device ofclaim 1 configured to generate the fourth unsaturated lightcorresponding to a plurality of points along a predefined path with thelight generated at each point having light with Rf greater than or equalto about 85, Rg greater than or equal to about 90 and less than or equalto about 110, or both.
 3. The semiconductor light emitting device of anypreceding claim configured to generate the fourth unsaturated lightcorresponding to a plurality of points along a predefined path with thelight generated at each point having light with Ra greater than or equalto about 92 along points with correlated color temperature between about1800K and 10000K, R9 greater than or equal to 80 along points withcorrelated color temperature between about 2100K and about 10000K, orboth.
 4. The semiconductor light emitting device of any preceding claimconfigured to generate the fourth unsaturated light corresponding to aplurality of points along a predefined path with the light generated ateach point having EML greater than or equal to about 0.5 along pointswith correlated color temperature above about 2400K, EML greater than orequal to about 1.0 along points with correlated color temperature aboveabout 5500K, or both.
 5. The semiconductor light emitting device of anypreceding claim configured to generate the fourth unsaturated lightcorresponding to a plurality of points along a predefined path with thelight generated at each point having light with R13 greater than orequal to about 92, R15 greater than or equal to about 88, or both. 6.The semiconductor light emitting device of any preceding claim, whereinthe blue color region comprises a region on the 1931 CIE ChromaticityDiagram defined by a line connecting the ccx, ccy color coordinates ofthe infinity point of the Planckian locus (0.242, 0.24) and (0.12,0.068), the Planckian locus from 4000K and infinite CCT, the constantCCT line of 4000K, the line of purples, and the spectral locus.
 7. Thesemiconductor light emitting device of any preceding claim, wherein thered color region comprises a region on the 1931 CIE Chromaticity Diagramdefined by the spectral locus between the constant CCT line of 1600K andthe line of purples, the line of purples, a line connecting the ccx, ccycolor coordinates (0.61, 0.21) and (0.47, 0.28), and the constant CCTline of 1600K.
 8. The semiconductor light emitting device of anypreceding claim, wherein the green color region comprises a region onthe 1931 CIE Chromaticity Diagram defined by the constant CCT line of6700K, the Planckian locus, and the spectral locus.
 9. The semiconductorlight emitting device of any preceding claim, wherein the green colorregion comprises a region on the 1931 CIE Chromaticity Diagram definedby a 60-step MacAdam ellipse centered approximately 65 points above thePlanckian locus at 4500K, the Planckian locus, and the constant CCT lineof 6700K.
 10. The semiconductor light emitting device of any precedingclaim, wherein the spectral power distribution for the red, channelfalls within the minimum and maximum ranges shown in Tables 1 and
 2. 11.The semiconductor light emitting device of any preceding claim, whereinthe spectral power distribution for the blue channel falls within theminimum and maximum ranges shown in Tables 1 and
 2. 12. Thesemiconductor light emitting device of any preceding claim, wherein thespectral power distribution for the green channel falls within theminimum and maximum ranges shown in Tables 1 and
 2. 13. Thesemiconductor light emitting device of any preceding claim, wherein thered channel has a spectral power distribution with spectral power in oneor more of the wavelength ranges other than the reference wavelengthrange increased or decreased within 30% greater or less, within 20%greater or less, within 10% greater or less, or within 5% greater orless than the values of a red channel shown in Tables 3 and
 4. 14. Thesemiconductor light emitting device of any preceding claim, wherein theblue channel has a spectral power distribution with spectral power inone or more of the wavelength ranges other than the reference wavelengthrange increased or decreased within 30% greater or less, within 20%greater or less, within 10% greater or less, or within 5% greater orless than the values of a blue channel shown in Tables 3 and
 4. 15. Thesemiconductor light emitting device of any preceding claim, wherein thegreen channel has a spectral power distribution with spectral power inone or more of the wavelength ranges other than the reference wavelengthrange increased or decreased within 30% greater or less, within 20%greater or less, within 10% greater or less, or within 5% greater orless than the values of a green channel shown in Table
 3. 16. Thesemiconductor light emitting device of any preceding claim, wherein thedevice further comprises a fourth LED string comprising one or moreLEDs.
 17. The semiconductor light emitting device of claim 16, whereinthe LEDs of the fourth LED string comprise a type of LED selected from380-420 nm violet saturated LEDs, 200-280 nm UVC saturated LEDs, 850-940nm near-IR saturated LEDs, 580-620 nm amber-orange/red saturated LEDs,and 460-490 nm long-blue saturated LEDs.
 18. The semiconductor lightemitting device of claim 16, wherein the LEDs of the fourth LED stringcomprise 380-420 nm violet saturated LEDs.
 19. The semiconductor lightemitting device of claim 16, wherein the LEDs of the fourth LED stringcomprise 200-280 nm UVC saturated LEDs.
 20. The semiconductor lightemitting device of claim 16, wherein the LEDs of the fourth LED stringcomprise 850-940 nm near-IR saturated LEDs.
 21. The semiconductor lightemitting device of claim 16, wherein the LEDs of the fourth LED stringcomprise 580-620 nm amber-orange/red saturated LEDs.
 22. Thesemiconductor light emitting device of any one of claims 16 to 21,wherein the control circuit is further configured to adjust a sixthcolor point of a sixth unsaturated light that results from a combinationof the first, second, and third unsaturated light and a fifth saturatedlight generated by the fourth LED string, with the sixth color pointfalls within a 7-step MacAdam ellipse around any point on the black bodylocus having a correlated color temperature between 1800K and 10000K.23. The semiconductor light emitting device of claim 22, wherein theLEDs of the fourth LED string comprise 380-420 nm violet saturated LEDsand wherein the device is configured to generate the sixth unsaturatedlight corresponding to a plurality of points along a predefined pathwith the light generated at each point having light with Rf greater thanor equal to about 85, Rg greater than or equal to about 95 and less thanor equal to about 103, or both.
 24. The semiconductor light emittingdevice of claim 22, wherein the LEDs of the fourth LED string comprise380-420 nm violet saturated LEDs and wherein the device is configured togenerate the sixth unsaturated light corresponding to a plurality ofpoints along a predefined path with the light generated at each pointhaving light with Rf greater than or equal to about 90, Rg greater thanor equal to about 97 and less than or equal to about 103, or both. 25.The semiconductor light emitting device of claim 22, wherein the LEDs ofthe fourth LED string comprise 380-420 nm violet saturated LEDs andwherein the device is configured to generate the sixth unsaturated lightcorresponding to a plurality of points along a predefined path with thelight generated at each point having light with Rf greater than or equalto about 90, Rg greater than or equal to about 99 and less than or equalto about 103, or both.
 26. The semiconductor light emitting device ofclaim 22, wherein the LEDs of the fourth LED string comprise 380-420 nmviolet saturated LEDs and wherein the device is configured to generatethe sixth unsaturated light corresponding to a plurality of points alonga predefined path with the light generated at each point having lightwith Rf greater than or equal to about 90, Rg greater than or equal toabout 97 and less than or equal to about 101, or both.
 27. Thesemiconductor light emitting device of claim 22, wherein the LEDs of thefourth LED string comprise 380-420 nm violet saturated LEDs and whereinthe device is configured to generate the sixth unsaturated lightcorresponding to a plurality of points along a predefined path with thelight generated at each point having light with Ra greater than or equalto about 93 along points with correlated color temperature between about1800K and 10000K, R9 greater than or equal to 85 along points withcorrelated color temperature between about 1800K and about 10000K, orboth.
 28. The semiconductor light emitting device of claim 22, whereinthe LEDs of the fourth LED string comprise 380-420 nm violet saturatedLEDs and wherein the device is configured to generate the sixthunsaturated light corresponding to a plurality of points along apredefined path with the light generated at each point having one ormore of EML greater than or equal to about 0.5 along points withcorrelated color temperature above about 2700K, EML greater than orequal to about 0.75 along points with correlated color temperature aboveabout 4000K, EML greater than or equal to about 1.0 along points withcorrelated color temperature above about 5500K, and EML greater than orequal to about 1.2 along points with correlated color temperature aboveabout 8000K.
 29. The semiconductor light emitting device of claim 22,wherein the LEDs of the fourth LED string comprise 380-420 nm violetsaturated LEDs and wherein the device is configured to generate thesixth unsaturated light corresponding to a plurality of points along apredefined path with the light generated at each point having light withR13 greater than or equal to about 94, R15 greater than or equal toabout 90, or both.
 30. The semiconductor light emitting device of claim22, wherein the LEDs of the fourth LED string comprise 380-420 nm violetsaturated LEDs and wherein the device is configured to generate thesixth unsaturated light corresponding to a plurality of points along apredefined path with the light generated at each point having light withR13 greater than or equal to about 95, R15 greater than or equal toabout 92, or both.
 31. The semiconductor light emitting device of claim22, wherein the LEDs of the fourth LED string comprise 380-420 nm violetsaturated LEDs and wherein the device is configured to generate thesixth unsaturated light corresponding to a plurality of points along apredefined path with the light generated at each point having light withR13 greater than or equal to about 94, R15 greater than or equal toabout 95, or both.
 32. The semiconductor light emitting device of anyone of claims 22-31, wherein the control circuit is configured toprovide two operating modes comprise a first operating mode thatgenerates light only using the blue, red, and green channels and asecond operating mode that generates light using the blue, red, andgreen channels and the fourth LED string.
 33. The semiconductor lightemitting device of claim 22-32, wherein the control circuit isconfigured to switch between the first operating mode and the secondoperating mode to provide the fourth unsaturated light and the sixthunsaturated light having substantially the same ccx, ccy coordinates onthe 1931 CIE Chromaticity Diagram.
 34. The semiconductor light emittingdevice of claim 33, wherein the six unsaturated light has an increasedRf by between about 2% and about 10% compared to the fourth unsaturatedlight.
 35. The semiconductor light emitting device of claim 33, whereinthe six unsaturated light has an increased Rf by between about 5% andabout 10% compared to the fourth unsaturated light.
 36. Thesemiconductor light emitting device of claim 33, wherein the sixunsaturated light has an Rg at least about 1 point closer to 100 ascompared to the fourth unsaturated light.
 37. The semiconductor lightemitting device of claim 33, wherein the six unsaturated light has an Rgat least about 2 points closer to 100 as compared to the fourthunsaturated light.
 38. The semiconductor light emitting device of claim33, wherein the six unsaturated light has an Rg at least about 3 pointscloser to 100 as compared to the fourth unsaturated light.
 39. Thesemiconductor light emitting device of claim 33, wherein the sixunsaturated light has an increased R9 by between about 2% and about 25%compared to the fourth unsaturated light.
 40. The semiconductor lightemitting device of claim 33, wherein the six unsaturated light has anincreased R9 by between about 5% and about 25% compared to the fourthunsaturated light.
 41. The semiconductor light emitting device of claim33, wherein the six unsaturated light has an increased R9 by betweenabout 5% and about 15% compared to the fourth unsaturated light.
 42. Thesemiconductor light emitting device of claim 33, wherein the sixunsaturated light has an increased Ra by between about 1% and about 3%compared to the fourth unsaturated light.
 43. The semiconductor lightemitting device of claim 33, wherein the six unsaturated light has anincreased Ra by between about 2% and about 3% compared to the fourthunsaturated light.
 44. The semiconductor light emitting device of claim33, wherein the six unsaturated light has an increased Ra by betweenabout 1% and about 4% compared to the fourth unsaturated light.
 45. Thesemiconductor light emitting device of claim 33, wherein the sixunsaturated light has an increased Ra by between about 2% and about 4%compared to the fourth unsaturated light.
 46. The semiconductor lightemitting device of claim 33, wherein the fourth unsaturated light andthe sixth unsaturated light have color points within about 1.0 standarddeviations of color matching (SDCM).
 47. The semiconductor lightemitting device of claim 33, wherein the fourth unsaturated light andthe sixth unsaturated light have color points within about 0.5 standarddeviations of color matching (SDCM).
 48. A method of generating whitelight, the method comprising: providing first, second, and third LEDstrings, with each LED string comprising one or more LEDs having anassociated luminophoric medium; providing a fourth LED string; whereinthe first, second, and third LED strings together with their associatedluminophoric mediums comprise red, blue, and green channelsrespectively; producing first, second, and third unsaturated light withcolor points within red, blue, and green regions on the 1931 CIEChromaticity diagram, respectively; providing a control circuitconfigured to adjust a fourth color point of a fourth unsaturated lightthat results from a combination of the first, second, and third,unsaturated light, with the fourth color point falls within a 7-stepMacAdam ellipse around any point on the black body locus having acorrelated color temperature between 1800K and 10000K, wherein thecontrol circuit is further configured to adjust a sixth color point of asixth unsaturated light that results from a combination of the first,second, and third unsaturated light and a fifth saturated light from thefourth LED string; generating light in a first operating mode with twoor more of the first, second, and third unsaturated light by combiningthe two or more generated unsaturated lights to create the fourthunsaturated light; and generating light in a second operating mode withtwo or more of the first, second, and third unsaturated light and thefifth saturated light by combining the two or more generatedunsaturated/saturated light to create the sixth unsaturated light. 49.The method of claim 48, wherein the LEDs of the fourth LED stringcomprise a type of LED selected from 380-420 nm violet saturated LEDs,200-280 nm UVC saturated LEDs, 850-940 nm near-IR saturated LEDs,580-620 nm amber-orange/red saturated LEDs, and 460-490 nm long-bluesaturated LEDs.
 50. The method of claim 48, wherein the LEDs of thefourth LED string comprise 380-420 nm violet saturated LEDs.
 51. Themethod of claim 48, wherein the LEDs of the fourth LED string comprise200-280 nm UVC saturated LEDs.
 52. The method of claim 48, wherein theLEDs of the fourth LED string comprise 850-940 nm near-IR saturatedLEDs.
 53. The method of claim 48, wherein the LEDs of the fourth LEDstring comprise 580-620 nm amber-orange/red saturated LEDs.
 54. Themethod of any one of claims 48-53, wherein the control circuit isconfigured to switch between the first operating mode and the secondoperating mode to provide the fourth unsaturated light and the sixthunsaturated light having substantially the same ccx, ccy coordinates onthe 1931 CIE Chromaticity Diagram.
 55. The method of claim 54, whereinthe fourth unsaturated light and the sixth unsaturated light have colorpoints within about 1.0 standard deviations of color matching (SDCM).56. The method of claim 54, wherein the fourth unsaturated light and thesixth unsaturated light have color points within about 0.5 standarddeviations of color matching (SDCM).
 57. The method of any one of claims54-56, wherein the sixth unsaturated light has improved color-renderingperformance in comparison to the fourth unsaturated light in one or moreof Ra, R9, Rf, and Rg.
 58. The method of claim 57, wherein the sixunsaturated light has an increased Rf by between about 2% and about 10%compared to the fourth unsaturated light.
 59. The method of claim 57,wherein the six unsaturated light has an increased Rf by between about5% and about 10% compared to the fourth unsaturated light.
 60. Themethod of claim 57, wherein the six unsaturated light has an Rg at leastabout 1 point closer to 100 as compared to the fourth unsaturated light.61. The method of claim 57, wherein the six unsaturated light has an Rgat least about 2 points closer to 100 as compared to the fourthunsaturated light.
 62. The method of claim 57, wherein the sixunsaturated light has an Rg at least about 3 points closer to 100 ascompared to the fourth unsaturated light.
 63. The method of claim 57,wherein the six unsaturated light has an increased R9 by between about2% and about 25% compared to the fourth unsaturated light.
 64. Themethod of claim 57, wherein the six unsaturated light has an increasedR9 by between about 5% and about 25% compared to the fourth unsaturatedlight.
 65. The method of claim 57, wherein the six unsaturated light hasan increased R9 by between about 5% and about 15% compared to the fourthunsaturated light.
 66. The method of claim 57, wherein the sixunsaturated light has an increased Ra by between about 1% and about 3%compared to the fourth unsaturated light.
 67. The method of claim 57,wherein the six unsaturated light has an increased Ra by between about2% and about 3% compared to the fourth unsaturated light.
 68. The methodof claim 57, wherein the six unsaturated light has an increased Ra bybetween about 1% and about 4% compared to the fourth unsaturated light.69. The method of claim 57, wherein the six unsaturated light has anincreased Ra by between about 2% and about 4% compared to the fourthunsaturated light.